Linguistic typology
Phonological typology

Linguistic typology also seeks to identify patterns in the structure and distribution of sound systems among the world's languages.This is accomplished by surveying and analyzing the relative frequencies of different phonological properties.Exemplary relative frequencies are given below for certain speech sounds formed by obstructing airflow (obstruents).These relative frequencies show that contrastive voicing commonly occurs with plosives, as in English neat and need, but occurs much more rarely among fricatives, such as the English niece and knees. According to a worldwide sample of 637 languages, 62% have the voicing contrast in stops but only 35% have this in fricatives.In the vast majority of those cases, the absence of voicing contrast occurs because there is a lack of voiced fricatives and because all languages have some form of plosive (occlusive), but there are languages with no fricatives.Below is a chart showing the breakdown of voicing properties among languages in the aforementioned sample.

Languages worldwide also vary in the number of sounds they use. These languages can go from very small phonemic inventories (Rotokas with six consonants and five vowels) to very large inventories (!Xóõ with 128 consonants and 28 vowels). An interesting phonological observation found with this data is that the larger a consonant inventory a language has, the more likely it is to contain a sound from a defined set of complex consonants (clicks, glottalized consonants, doubly articulated labial-velar stops, lateral fricatives and affricates, uvular and pharyngeal consonants, and dental or alveolar non-sibilant fricatives). Of this list, only about 26% of languages in a survey of over 600 with small inventories (less than 19 consonants) contain a member of this set, while 51% of average languages (19-25) contain at least one member and 69% of large consonant inventories (greater than 25 consonants) contain a member of this set. It is then seen that complex consonants are in proportion to the size of the inventory.

Vowels contain a more modest number of phonemes, with the average being 5–6, which 51% of the languages in the survey have. About a third of the languages have larger than average vowel inventories. Most interesting though is the lack of relationship between consonant inventory size and vowel inventory size. Below is a chart showing this lack of predictability between consonant and vowel inventory sizes in relation to each other.
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