The spelling of the word "most barrelling" can be explained using the International Phonetic Alphabet (IPA). The first syllable "most" is pronounced as /moʊst/ with the long o sound represented by /oʊ/ and the unstressed t at the end is silent. The second syllable "barrelling" is pronounced as /ˈbærəlɪŋ/ with the primary stress on the second syllable and the British English pronunciation of /ɛ/ sound in "barrel" represented by /ɛə/. The suffix "-ing" is pronounced as /ɪŋ/.