Weak forms of function words may be realized without vowel sounds, as in I can go [aɪ kŋ̍ ˈɡoʊ] and I must sell [aɪ ms̩ ˈsɛl].[13] Some of these forms are reflected in orthography as contractions, such as 's, 'll, 'd, and n't. (These can invoke syllabic consonants.)