Proto-Uralic is the reconstructed language ancestral to the Uralic language family. The language was originally spoken in a small area in about 7000–2000 BCE (estimates vary), and expanded to give differentiated protolanguages. The exact location of the area or Urheimat is not known, and various strongly differing proposals have been advocated, but the vicinity of the Ural Mountains is usually assumed.
According to the traditional binary tree model, Proto-Uralic diverged into Proto-Samoyedic and Proto-Finno-Ugric. However, reconstructed Proto-Finno-Ugric differs little from Proto-Uralic, and many apparent differences follow from the methods used. Thus Proto-Finno-Ugric may not be separate from Proto-Uralic. Another reconstruction of the split of Proto-Uralic has three branches (Finno-Permic, Ugric and Samoyedic) from the start. Recently these tree-like models have been challenged by the hypothesis of larger number of protolanguages giving a "comb" rather than a tree. The protolanguages would be Sami, (Baltic‑)Finnic, Mordva, Mari, Permic, Magyar, Khanti, Mansi, and Samoyedic. This order is both the order of geographical positions as well as linguistic similarity, with neighboring languages being more similar than distant ones.
Proto-Uralic had vowel harmony and a rather large inventory of vowels in initial syllables, much like the modern Finnish or Estonian system:
|Close||i /i/||ü /y/||ï /ɯ/||u /u/|
|Mid||e /e/||o /o/|
|Open||ä /æ/||a /ɑ/|
Sometimes a mid vowel *ë /ɤ/ is reconstructed in place of *ï, or a low back rounded *å /ɒ/ in place of *a.
There were no monophonemic long vowels nor diphthongs, though sequences of vowel and semivowel within a single syllable (such as *äj) could exist.
Vowel inventory in non-initial syllables was restricted: only a two-way contrast of open and non-open vowels is incontestably reconstructible. The actual realization of this contrast is a question of debate: one view considers this two archiphonemic vowels //a// and //i//, realized as four allophones [æ ɑ], [i ɯ] as per vowel harmony.
For the non-open vowel(s), most branches reflect a reduced vowel [ə]; only two branches give evidence for a specific value:
- The Finnic languages show /e/ or /ɤ/ depending on harmony, word-finally /i/.
- The Samic languages show a variety of reflexes, but these reflexes can be traced back to a Proto-Samic phoneme *ë, which is also the reflex of Proto-Uralic *i and *ü in stressed syllables.
While vowel reduction is a common sound change, Finnic is known to have adstrate influence from language groups that would not have known reduced vowels (namely the Baltic languages and the early Germanic languages), so a value of [ə] already in Proto-Uralic remains a possibility.
Although these three or four stem types were certainly the most prominent ones in Proto-Uralic, it is possible that other, rarer types may have existed as well. These include for example kinship terms such as "sister-in-law", found as *kälü in both Proto-Finnic and Proto-Samoyedic. Janhunen (1981) and Sammallahti (1988) reconstruct here instead a word-final labial glide: *käliw.
A general difficulty in reconstructing unstressed vowels for Proto-Uralic lies in their heavy reduction and loss in many of the Uralic languages. Especially in the Ugric and Permic languages, almost no trace of unstressed vowels appears in basic word roots. The original bisyllabic root structure has been well preserved in only the more peripheral groups: Samic and Finnic in the northwest, Samoyedic in the east. The main correspondences of unstressed vowels between these are as follows:
|*-a||*-ē [eː]||*-a [ɑ]||*-å [ɒ]|||
|*-ä||*-ä [æ]||*-ä [æ]|||
|*-ə||*-ë [ɤ]||*-e||∅||after original open syllables |
|*-ə||after original closed syllables |
Developments in Mordvinic and Mari are rather more complicated. In the former, Proto-Uralic *-a and *-ä are usually reduced to *-ə; *-a is however regularly retained whenever the first syllable of the word contained *u. Proto-Uralic *-ə is regularly lost after open syllables, as well as in some other positions.
Conditional vowel shifts
A number of roots appear to diverge from the main picture of unstressed syllables in a different way: while Finnic, Samic and Samoyedic languages all have one of the "typical" stem shapes, they may not quite match. Words in these classes often feature discrepancies in the vowels of the first syllable as well, e.g. Finnic *a or *oo (suggesting Proto-Uralic *a or *ë) against Samic *ā (suggesting Proto-Uralic *ä) or *oa (suggesting Proto-Uralic *o).
A number of such cases may result simply from conditional vowel shifts in unstressed syllables. In fact, multiple vowel shifts are reconstructed in branches of Uralic sensitive to a particular combination of stem vowel and following reduced vowel, in which both change at once. A shift *a-ə > *o-a can be posited for Samic as well as the Mordvinic languages. E.g.:
|*čoarvē < *ćorwa||Erzya сюро /sʲuro/
Moksha сюра /sʲura/
|*čoalē < *ćola||Erzya сюло /sʲulo/
Moksha сюра /sʲula/
|*sooli < *sali||-||||'intestine'|
|*koalō- < *kola(w)-||Erzya куло- /kulo-/
Moksha куло- /kulə-/
|*koole- < *kali-||*kåə-||hal||'to die'|
|*koamtē < *komta||Erzya and Moksha
|*kanci < *kanti||-||-||Mari комдыш /komdəʃ/||'lid'|
The change is, however, masked by the shift of *ë to *a (which later develops to Proto-Samic *uo) in words such as:
|*ńuolë < *ńalə||Erzya, Moksha нал /nal/||*nooli < *nali||*ńël||nyíl||'arrow'|
|*suonë < *sanə||Erzya, Moksha сан /san/||*sooni < *sani||*cën||ín||'vein, sinew'|
|*θuomë < *δamə||Erzya лём /lʲom/
Moksha лайме /lajmɛ/
|*toomi < *tami||*jëm||-||'bird cherry'|
|*vuoptë < *aptə||-||*(h)apci < *apti||*ëptə||-||'hair'|
In a second group, a change *ä-ä > *a-e appears to have taken place in Finnic in words such as:
|*loomi < *lami||-||-||-||Erzya леме /lʲeme/||'scab'|
|*pooli < *pali||*pealē||*pälä||fél||Erzya пеле /pelʲe/||'half'|
|*sappi||*sāppē||-||epe||Erzya сэпе /sepe/||'gall'|
|*talvi||*tālvē||-||tél||Erzya теле /tʲelʲe/||'winter'|
|*vaski||*veaškē||*wäsa||vas||Mari -вож /βoʒ/ 'ore'||'copper, bronze' ~ 'iron'|
In the consonant system, palatalization, or palatal-laminal instead of apical articulation, was a phonemic feature, as it is in many modern Uralic languages. Only one series of stops (unvoiced unaspirated) existed:
|p /p/||t /t/||(ć /t͡sʲ ~ t͡ɕ/)||č /t̠͡ʃ/||k /k/|
|Nasal||m /m/||n /n/||ń /nʲ ~ ɲ/||ŋ /ŋ/|
|Sibilant||s /s/||ś /sʲ ~ ɕ/||(š /ʃ/)|
|Spirants||δ /ð/||δ´ /ðʲ/|
|Lateral||l /l/||(ľ /lʲ ~ ʎ/)|
|Semivowel||w /w/||j /j/|
The phonetic nature of the segment symbolized by *x is uncertain, though it is usually considered a back consonant; [x], [ɣ], [ɡ], and [h] have been suggested among others. Janhunen (1981, 2007) takes no explicit stance, leaving open the option for even a vocalic value. The segment has some similarity to the Indo-European laryngeals (to which it can correspond in loanwords): it is reconstructed by certain scholars in syllable-final position in word-stems where a contrastive long vowel later developed (similar to Turkish ğ), best preserved in the Finnic languages, and where Samoyedic features a vowel sequence such as *åə. The correlation between these two stem classes is however not perfect, and alternate possibilities exist for explaining both vowel length in Finnic and vowel sequences in Samoyedic. *x is also reconstructed word-medially, and in this position it also develops to a Finnic long vowel, but has clear consonantal reflexes elsewhere: *k in Samic, *j in Mordvinic and *ɣ in Ugric. If a consonant, it probably derives from lenition of *k at a pre-Uralic stage; it is only found in words ending in a non-open vowel, while *k is infrequent or nonexistent in similar positions.
The phonetical identity of the consonant *δ´ is also subject to some doubt. It is traditionally analyzed as the palatalized counterpart of the voiced dental fricative *δ, that is, as [ðʲ]; however, this a typologically rare sound value for which no direct evidence is found in any Uralic language, and a pure palatal fricative [ʝ] is another option; a third option is a palatal liquid like, e. g., Czech ř. Some others propose to adjust the sound values of both this consonant and its plain counterpart. Ugricist László Honti has advanced a reconstruction with lateral fricatives: [ɬ], [ɬʲ] for *δ, *δ´, while Frederik Kortlandt reconstructs palatalized [rʲ] and [lʲ], alleging that they pattern like resonants.
The phonemes in parentheses—*ć, *š, *ĺ—are supported by only limited evidence, and are not assumed by all scholars. Sammallahti (1988) notes that while instances of *ć are found in all three of Permic, Hungarian and Ob-Ugric, there are "very few satisfactory etymologies" showing any correlation between the branches in whether *ć or *ś appears. In the other languages, no consistent distinction between these consonants is found. The evidence for the postalveolar sibilant *š however is "scarce but probably conclusive" (ibid): it is treated distinctly from *s only in the more western (Finno-Permic) languages, but certain loans from as far back as the Proto-Indo-European language have reflexes traceable to a postalveolar fricative (including *piši- or *peši- "to cook"). The possibility of *ĺ is not considered by him at all. In contrast, Janhunen, who considers Samoyedic evidence necessary for conclusions about Proto-Uralic, doubts that *š can be reconstructed, preferring to consider it a secondary, post-Proto-Uralic innovation (p. 210). He agrees with Sammallahti in omitting *ĺ and in only considering a single palatal obstruent as necessary to reconstruct; for the latter he suggests the sound value of a palatal stop, [c] (p. 211).
No initial or final consonant clusters were allowed, so words could begin and end with a maximum of one consonant only. The single consonants *δ *r *x *ŋ also could not occur word-initially, though at least for the first of these, this may be an coincidental omission in the data. A reconstruction *δäpδä "spleen" exists but is not found in Samoyedic and the most stringent criteria for a Proto-Uralic root thus exclude it. A similar case is *repä "fox", a loanword from Indo-Iranian.
Inside word roots, only clusters of two consonants were permitted. Since *j and *w were consonants even between a vowel and another consonant, there were no sequences of a "diphthong" followed by two consonants, like in e.g. Finnish veitsi. While voicing was not a phonemic feature, double (i.e. geminate) stops probably existed (*ïppi "father-in-law", *witti "five", *lükkä- "to push"). The singleton–geminate contrast in most descendant languages developed into a voiced–voiceless distinction, although Finnic is a notable exception, e.g. Finnish appi, lykkää.
When, due to suffixation, consonant clusters arose that were not permitted, the non-low vowel was inserted as a prop vowel. This process was obscured in the Finnic languages by an opposing process which syncopated unstressed *e in many cases.
Proto-Uralic did not have tones, which contrasts with Yeniseian and some Siberian languages. Neither was there contrastive stress as in Indo-European; in Proto-Uralic the first syllable was invariably stressed.
Consonant gradation may have occurred already in Proto-Uralic: if it did, it was probably a phonetical alternation involving allophonic voicing of the stop consonants: [p] ~ [b], [t] ~ [d], [k] ~ [g].
Proto-Uralic nouns are reconstructed with at least six noun cases and three numbers, singular, dual and plural. Grammatical gender was not recognized and no Uralic language does so even today. Noun articles were unknown.
The plural marker of nouns was *-t in final position and *-j- in non-final position, as seen in Finnish talot and talojen ("house" Pl.Nom and Pl.Gen). The dual marker has been reconstructed as *-k-, but the dual number has been lost in many of the contemporary Uralic languages.
The cases were:
- nominative (no suffix)
- accusative *-m
- dative/genitive *-n
- locative *-na / *-nä
- ablative/instrumentative *-ta / *-tä
- lative *-ŋ
The cases had only one three-way locative contrast of entering, residing and exiting (lative, locative and ablative respectively). This is the origin of the three-way systems as the three different ones in Karelian Finnish (illative/inessive/elative, allative/adessive/ablative, translative/essive/exessive). The partitive case, developed from the ablative, was a later innovation in the Finnic and Samic languages. Further cases are occasionally mentioned, e.g. Robert Austerlitz's reconstruction of Proto-Finno-Ugric includes a seventh, adverbial.
The nouns also had possessive suffixes, one for each combination of number and person. These took the place of possessive pronouns, which did not exist.
Verbs were conjugated at least according to number, person and tense. The reconstructions of mood markers are controversial. Some scholars argue that there were separate subjective and objective conjugations, but this is disputed; clear reflexes of the objective conjugation are found in only the easternmost branches, and hence it may also represent an areal innovation. Negation was expressed with the means of a negative verb *e-, found as such in e.g. Finnish e+mme "we don't".
Merlijn De Smit of Stockholm University has argued for ergativity in Proto-Uralic, reinterpreting the accusative case as a lative one and arguing for a marked subject via the genetive case and a verbal ending, *mV-. Support for this theory comes from the Finnish agent participle constructions, e.g. miehen ajama auto — car driven by the man, Naisen leipoma kakku — the cake that woman baked.  In these constructions the subject, which is usually unmarked, is in the genetive case, while the direct object, usually marked with -n is unmarked.
This resembles a passive construction such as pater amatur a filio, filio being declined in the dative case, except that the word order in Finnish is reversed.
This construction also occurs in Nashi, Mari, Mordvinic (the -mV participle is absent), and Karelian. However, unlike Finnish, the construction is also used with intransitive sentences, characterized by the same -mV suffix on the verb, e.g. Udmurt gyrem busy, “a ploughed field, a field that has been ploughed”, lyktem kišnomurt, “the arrived lady, the lady who has arrived”. The -mV participle ending in Mari denotes a preterite passive meaning, e.g. in Eastern Mari omtam počmo, “the door (has been) opened”, təj kaləkən mondəmo ulat, “you are forgotten by the people”, and memnan tolmo korno, “the road that we have come”. 
This is problematic for the ergative theory because the -mV participle, labled the ergative marker, is a passive marker in most of the languages that use it, and the Finnish agent participle constructions may in fact derive from similiar constructions in Baltic languages, e.g. Lithuanian tėvo perkamas automobilis or automobilis (yra) tėvo perkamas. Notable is the unmistakable resemblance between the Baltic and Finnic verbal suffixes, and the fact that -mV is missing in both Estonian and Mordvinic, despite being two very close relatives of Finnish. However, the Baltic participle in -ma does not represent the most common Indo-European ending of a passive participle, even though it does have parallels in ither Indo-European languages.  Even if the ending derives from Proto-Uralic and not the Baltic languages, the transition from a passive to ergative construction is very common and has been observed in Indo-Aryan, Salish, and Polynesian. The transition begins when the unmarked subject of the passive sentence, usually marked in active sentences (if the language is inflectional), is re-analyzed as an unmarked absolutive, and the marked agent as ergative. 
Only some 200 word roots can be reconstructed for Proto-Uralic, if it is required that every word reconstructed for the proto-language should be present in Samoyedic languages (related to the hypothesis that Samoyedic was the first group to split off: see discussion at Finno-Ugric languages). With a laxer criterion of reconstructing words which are attested in most branches of the language family, a number in the range of 300–400 roots can be reached.
The following examples of reconstructed items are considered to fulfill the strictest criteria and are thus accepted as Proto-Uralic words by practically all scholars in the field:
- Body parts and bodily functions: *ïpti hair on the head, *ojwa head, *śilmä eye, *poski cheek, *kä(x)li tongue/language, *mïksa liver, *elä- to live, *ka(x)li- to die, *wajŋi breath, *kosi cough, *kunśi urine, *küńili tear, *se(x)ji pus.
- Kinship terms: *emä mother, *čečä uncle, *koska aunt, *mińä daughter-in-law, *wäŋiw son-in-law.
- Verbs for universally known actions: *meni- to go, *toli- to come, *aśkili- to step, *imi- to suck, *soski- to chew, *pala- to eat up, *uji- to swim, *sala- to steal, *kupsa- to extinguish, *tumti- to know.
- Basic objects and concepts of the natural world: *juka river, *toxi lake, *weti water, *päjwä sun/warmth, *kala fish, *suŋi summer, *śala- lightning, *wanča root, *ko(x)ji birch, *ka(x)si spruce, *sïksi Siberian pine, *δ´ï(x)mi bird cherry, *muna egg.
- Elementary technology: *tuli fire, *śüδi coal, *äjmä needle, *pura drill/to bore, *jïŋsi bow, *jänti bow string, *ńï(x)li arrow, *δ´ümä glue, *lïpśi cradle, *piksi rope, *suksi ski, *woča fence.
- Basic spatial concepts: *ïla below, *üli above, *wasa left, *pälä "half", *pe(x)li side.
- Pronouns: *mun I, *tun you, *ke- who, *mi- what.
A reconstruction of a word *wäśkä, meaning 'reddish metal' (copper, bronze or iron), has also been proposed. However, this word shows irregularities in sound correspondence, and some scholars believe it to be a Wanderwort instead.
The reconstructed vocabulary is compatible with a Mesolithic culture (bow, arrow, needle, sinew, but also rope, fence, cradle, ski), a north Eurasian landscape (spruce, birch, Siberian pine), and contains interesting hints on kinship structure.
Examples of vocabulary correspondences between the modern Uralic languages are provided in the list of comparisons at the Finnish Wikipedia.
In popular culture
- The film Unna ja Nuuk (2006) has extensive dialogue in reconstructed Proto-Finno-Samic (Early Proto-Finnic), the proto-language of the Finno-Samic languages.
- Janhunen 1981a pp. 24–25
- Helimski 1984, p. 248.
- Petri, Kallio (2012), "The non-initial-syllable vowel reductions from Proto-Uralic to Proto-Finnic", Suomalais-Ugrilaisen Seuran toimituksia, 264, ISSN 0355-0230
- Helimski 1984, p. 249.
- Janhunen 1981, pp. 2–3.
- Janhunen 1981, p. 6.
- Janhunen 1981, p. 12.
- Janhunen 1981, pp. 16-17.
- Ravila, Paavo (1929), "Über eine doppelte vertretung des urfinnischwolgaischen *a der nichtersten silbe im mordwinischen", Finnisch-Ugrische Forschungen, 20, ISSN 0355-1253
- Aikio, Ante (2013), Uralilaisen kantakielen vokaalistosta
- Possibly szál 'thread'
- Zhivlov, Mikhail (2014), "Studies in Uralic Vocalism III", Journal of Language Relationship, 12
- Janhunen, Juha (2007), "The primary laryngeal in Uralic and beyond" (pdf), Suomalais-Ugrilaisen Seuran toimituksia, 253, ISSN 0355-0230, retrieved 2010-05-05
- Aikio, Ante (2012), "On Finnic long vowels, Samoyed vowel sequences, and Proto-Uralic *x", Suomalais-Ugrilaisen Seuran toimituksia, 264, ISSN 0355-0230
- László, Honti (2013), "Comments on Uralic historical phonology" (pdf), Acta Linguistica Hungarica, 60: 1–68, doi:10.1556/ALing.60.2013.1.1, ISSN 1588-2624, retrieved 2013-04-10
- Helimski, Eugene. Proto-Uralic gradation: Continuation and traces – In: Congressus Octavus Internationalis Fenno-Ugristarum. Pars I: Orationes plenariae et conspectus quinquennales. Jyväskylä, 1995. "Archived copy" (PDF). Archived from the original (PDF) on 2011-10-02. Retrieved 2012-02-24.CS1 maint: Archived copy as title (link)
- Maria Polinsky, Circum-Baltic Languages: Volume 1: Past and Present, Oxford University Press 2016, p 248
- Maria Polinsky, Circum-Baltic Languages: Volume 1: Past and Present, Oxford University Press 2016, p 249
- Elena E. Kuz'mina, Deconstructing Ergativity: Two Types of Ergative Languages and Their Features, edited by Östen Dahl, Maria Koptjevskaja-Tamm, Oxford University Press 2016, p 30
- Janhunen, Juha. 1981a. "On the structure of Proto-Uralic." Finnisch-ugrische Forschungen 44, 23–42. Helsinki: Société finno-ougrienne.
- Janhunen, Juha. 1981b. "Uralilaisen kantakielen sanastosta ('On the vocabulary of the Uralic proto-language')." Journal de la Société Finno-Ougrienne 77, 219–274. Helsinki: Société finno-ougrienne.
- Helimski, Eugene (1984), Problems of phonological reconstruction in modern Uralic linguistics
- Sammallahti, Pekka. 1988. "Historical phonology of the Uralic languages, with special reference to Samoyed, Ugric, and Permic." In The Uralic Languages: Description, History and Foreign Influences, edited by Denis Sinor, 478–554. Leiden: Brill.