In the English alphabet, it's the only polysyllabic letter
.... Nine letter 
monosyllabic words are scratched, screeched, scrounged, squelched, straights,... [DOC] [TLE] 14 of the Longest Words in English | Grammarly Blog [PAR] Aug 30, 2016 ... 7 Strengths has only nine letters, but all except one of them are consonants!