In phonology and historical linguistics, cluster reduction is the simplification of consonant clusters in certain environments or over time.
In some dialects of English such as AAVE certain historical consonant clusters reduce to single consonants at the ends of words: friend rhymes with Ben, and cold is homophonous with coal. In both cases, a historical cluster of homorganic consonants loses a stop: /ˈfrɛn/, /ˈkoʊl/ However, in colder, where the consonant cluster falls between vowels, the /d/ remains: /ˈkoʊldɚ/. The similar word-final reduction of */mb/ to /m/ and */ŋɡ/ to /ŋ/ is complete in standard English (e.g. lamb, long), as it is in many other Germanic languages (e.g. Swedish lamm, lång).