Qualitative typology develops cross-linguistically viable notions or types that provide a framework for the description and comparison of languages.
The main subfields of linguistic typology include the empirical fields of syntactic, phonological and lexical typology. Additionally, theoretical typology aims to explain the empirical findings, especially statistical tendencies or implicational hierarchies.
Syntactic typology studies a vast array of grammatical phenomena from the languages of the world. Two well-known issues include dominant order and left-right symmetry.
On the other hand, when there is no clear preference under the described conditions, the language is considered to have "flexible constituent order" (a type unto itself).
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.