Enclitic

A word that is pronounced with so little emphasis that it is treated as part of the preceding word to which it is appended. In English, e.g., we can say, "We've," instead of "We have." In the first instance, the verb 'have' has been so contracted in pronounciation that it is treated as part of the personal pronoun 'we,' and is said to be enclitic (used here as an adjective).