The acceptable sound combinations of a language are specified in its _____ rules.

Phonological rules specify the acceptable sound combinations in a language. Phonology is the study of how sounds are organized and used in natural languages, including which sound combinations are permissible. Each language has its own phonological rules that govern which sounds can occur together and in what positions within words. Grammatical and syntactic rules concern word and sentence structure, while inflection deals with word forms.