1. A method comprising: based on characteristics of a first unit of input speech, selecting a gender-specific speaker adaptation technique, wherein the gender-specific speaker adaptation technique relates to a particular gender; conducting, by a computing device, automatic speech recognition (ASR) of a second unit of input speech, wherein the ASR of the second unit of input speech is based on the gender-specific speaker adaptation technique; while conducting the ASR of the second unit of input speech, selecting a speaker-dependent speaker adaptation technique, wherein the speaker-dependent speaker adaptation technique is based on characteristics of the second unit of speech and relates to a particular speaker of the particular gender; and conducting ASR of a third unit of input speech, wherein the ASR of the third unit of speech is based on the speaker-dependent speaker adaptation technique.
2. The method of claim 1 , further comprising: determining that the third unit of input speech was originated proximate to a particular location; based on the third unit of input speech being originated proximate to the particular location and characteristics of the third unit of speech, selecting an environment-specific, speaker-dependent speaker adaptation technique, wherein the environment-specific, speaker-dependent speaker adaptation technique is associated with the particular location; and conducting ASR of a fourth unit of input speech, wherein the ASR of the fourth unit of input speech is based on the environment-specific, speaker-dependent speaker adaptation technique.