Table 2.

Models of speech perception, including units emphasized during signal analysis in the model, and the units used to match with stored memory representations. In many models, but not all, these units coincide (see Frauenfelder & Floccia, 1999; Pisoni & Luce, 1987, for discussion)

Units of speech perceptual analysis	Units of lexical coding	Examples
Spectra	Auditory objects	Diehl and Kluender (1987); Diehl, Lotto and Holt (2004)
Spectra	Spectra	Klatt (1979, 1980, 1989; LAFS)
Features	Features	Stevens (1986, 1992; LAFF); Lahiri and Reetz (2002)
Gestures	Gestures	Zhuang, Nam, Hasegawa-Johnson, Goldstein, and Saltzman (2009); Mitra, Nam, Espy-Wilson, Saltzman, and Goldstein (2010)
Allophones	Allophones	Lowerre (1976; Harpy); Mitterer, Scharenborg, and McQueen (2013)
Triphones (allophones with one segment of left and right context)	Triphones	Wickelgren (1969; numerous HMM models); Laface and De Mori (1990)
Allophones	Phonemes	Church (1987a, 1987b); Whalen (1991)
Robust features	Phonemes	Huttenlocher and Zue (1984)
Multiple phoneme probabilities	Phonemes	Norris and McQueen (2008)
Demi-syllable (sometimes also called ‘diphone’)	Demi-syllable	Fujimura (1976); Rosenberg, Rabiner, Wilpon, and Kahn (1983)
Syllable	Syllable	Fujimura (1975); Smith (1977; Hearsay II); Smith and Erman (1981; Noah); Ganapathiraju, Hamaker, Picone, Ordowski, and Doddington (2001); Greenberg (2006)
Word vector	Word template	Rabiner and Levinson (1981)
Fine detail	Word exemplars	Palmeri, Goldinger, and Pisoni (1993)
Fine detail & allophones	Word exemplars	Pierrehumbert (2002)