While roots are typical in Sanskrit, some words do not follow the canonical structure. A few forms lack both inflection and root. Many words are inflected (and can enter into derivation) but lack a recognizable root. Examples from the basic vocabulary include kinship terms such as "mātar-" (mother), "nas-" (nose), "śvan-" (dog). According to Jamison, pronouns and some words outside the semantic categories also lack roots, as do the numerals. Similarly, the Sanskrit language is flexible enough to not mandate inflection.