Languages use many different speech sounds, but the number of sounds can vary greatly from one language to another. Rotokas, a language spoken in Papua New Guinea, has only 11 phonemes and Hawaiian has only 13. However, a few languages have over 60 phonemes. They include languages spoken in southern Africa, North America and the Caucasus.
The most common consonants are voiced and voiceless bilabial, alveolar and velar plosives, bilabial, alveolar, palatal and velar nasals, the glottal stop, labiodental, alveolar, alveopalatal and glottal fricatives, and also liquids and glides. The most common vowels are the low vowel (central or back), the high front unrounded vowel and the high back rounded vowel.
Languages usually have fewer vowels than consonants. Average vowel inventories consist of five to six vowels. Large vowel inventories are predominantly found in Africa, Asia and Europe. It is often the case that a language with many consonants, i.e., Russian, has relatively few vowels, and a language with many vowels, i.e., Finnish, has relatively few consonants.
The consonant-vowel ratio of a language is calculated by dividing the number of consonants by the number of vowels. The numbers range from a little over 1 to as high as 29. The language of Andoke, spoken in Colombia, has 10 consonants and 9 vowels. The consonant-vowel ratio is thus 1.1. In contrast, Abkhaz, a language spoken in Georgia, has 58 consonants but only 2 vowels which results in a very high consonant-vowel ratio of 29.
Though languages use a great variety of speech sounds, the number and type differ significantly. Most languages use from 30 to 60 sounds. The most common speech sounds are not present in all languages. Many North American languages lack bilabials, and several Australian languages lack fricatives.