Describe phones in terms of articulatory positions All languages can be described within a single system Acoustic similarity of phones can be predicted Examples: PHONE DESCRIPTION S UNVOICED ALVEOLAR FRICATIVE F UNVOICED LABIO-DENTAL FRICATIVE II HIGH FRONT UNROUND LONG VOWEL
	Map recognition phone sets onto the International Phonetic Alphabet (IPA) Map phone sets from source language to target language Selectively mix phone sets across languages Cluster phones according to acoustic phonetic similarity