Inventories

A comparative, typological approach is often employed in the study of phonological segment inventories. It has been observed that certain kinds of segments occur in very many languages, while others occur in only a few. This observation is embodied in the study of markedness, which is the idea that not all segments or sets of segments or rules have equal status in phonological systems. For example, many languages have the stop consonants [p t k], a system that is said to be unmarked, but relatively few have the uvular [q], which is said to be marked. Markedness is a comparative concept, so [q] is more marked than [k] but less marked than [ʕ]. Many languages have the voiced approximant [l], but few have the voiceless lateral fricative [ɬ] and even fewer have the voiced lateral fricative [ɮ]. Very many languages have the vowels [i e a o u]; not many have the vowels [ɨ œ ʊ ɪ].

Related to frequency of segment types across languages is the concept of implicational relation. An example of an implicational relation is that holding between oral and nasal vowels. Many languages have only oral vowels (Spanish, German), and many languages have both oral and nasal vowels (French, Portuguese), but no language has only nasal vowels; that is, the existence of nasal vowels implies the existence of oral vowels. All languages have voiced sonorant consonants, and some additionally have voiceless sonorants; no language has only voiceless sonorants. Or, many languages have only a voiceless series of obstruents, others have both voiced and voiceless obstruents; but none has only voiced obstruents.

The method of comparing inventories. Three methodological issues need to be borne in mind when conducting such typological studies. First, determining what is more common versus less common requires a good-sized random sample of the languages of the world. However, information on phonological structure is not easily available for many of the languages of the world, and existing documentation tends to favor certain languages (for example the Indo-European languages) over other languages (those of New Guinea).

Second, it is often difficult to determine the true phonetic values of segments in a language which you do not know, so interpreting a symbol in a grammar may result in error. The consonants spelledmay in fact be ejective [p’ t’ k’], butare used in the spelling system because p, t, k are “more basic” segments and the author of a grammar may notate ejectives with “more basic” symbols if no plain nonejective voiceless stops exist in the language. This is the case in many Bantu languages of Southern Africa, such as Gitonga and Zulu, which contrast phonetically voiceless aspirated and ejective stops – there are no plain unaspirated voiceless stops. Therefore, the ejectives are simply writtenbecause there is no need to distinguish [p] and [p’]. This phonetic detail is noted in some grammars, but not in all, and if you do not have experience with the language and do not read a grammar that mentions thatis ejective, you might not notice that these languages have no plain voiceless stops.

Third, many typological claims are statistical rather than absolute – they are statements about what happens most often, and therefore encountering a language that does not work that way does not falsify the claim. It is very difficult to refute a claim of the form “X is more common than Y,” unless a very detailed numerical study is undertaken.

Typical inventories. With these caveats, here are some general tendencies of phoneme inventories. In the realm of consonantal place of articulation, and using voiceless consonants to represent all obstruents at that place of articulation, the places represented by [p, t, k] are the most basic, occurring in almost all languages of the world. The next most common place would be alveopalatal; less common are uvulars, dentals, and retroflex coronals; least common are pharyngeal. All languages have a series of simple consonants lacking secondary vocalic articulations. The most common secondary articulation is rounding applied to velars, then palatalization; relatively uncommon is rounding of labial consonants; least common would be distinctive velarization or pharyngealization of consonants. Among consonants with multiple closures, labiovelars like [kp] are the most common; clicks, though rare, seem to be more common than linguolabials.

In terms of manners of consonant articulation, stops are found in all languages. Most language have at least one fricative (but many Australian languages have no fricatives), and the most common fricative is ʃ, followed by f and ʃ, then x, then θ and other fricatives. The most common affricates are the alveopalatals, then the other coronal affricates; pf and kx are noticeably less frequent. In terms of laryngeal properties of consonants, all languages have voiceless consonants (in many, the voice onset time of stops is relatively long and the voiceless stops could be considered to be phonetically aspirated). Plain voiced consonants are also common, as is a contrast between voiceless unaspirated and voiceless aspirated stops. Ejectives, implosives and breathy voiced consonants are much less frequent. Among fricatives, voicing distinctions are not unusual, but aspiration, breathy voicing and ejection are quite marked.

Nearly all languages have at least one nasal consonant, but languages with a rich system of place contrasts among obstruents may frequently have a smaller set of contrasts among nasals. Most languages also have at least one of [r] or [l], and typically have the glides [w j]. Modal voicing is the unmarked case for liquids, nasals, and glides, with distinctive laryngealization or devoicing/aspiration being uncommon. Among laryngeal glides, [h] is the most common, then [ʔ], followed by the relatively infrequent [ɦ].

The optimal vowel system would seem to be [i e a o u], and while the mid vowels [e o] are considered to be more marked than the high vowels [i u] for various reasons having to do with the operation of phonological rules (context-free rules raising mid vowels to high are much more common than context-free rules lowering high vowels to mid), there are fewer languages with just the vowels [i u a] than with the full set [i u e o a]. The commonness of front rounded and back unrounded vowels is correlated with vowel height, so a number of languages have [y] and not [ø], but very few have [ø] and not [y]. Full exploitation of the possibilities for low back and round vowels [ae ɶ a ɒ] is quite rare, but it is not hard to find languages with [i y ɨ u]. As noted earlier, oral vowels are more common than nasal vowels, and modal voiced vowels are more common than creaky-voiced or breathy vowels.