The word "Irrelapsable" is spelled with the prefix "ir-" meaning "not", then followed by "relapsable" meaning "unable to relapse or fall back". The phonetic transcription for this word is /ɪrɪ'læpsəbl/ where the stress is on the second syllable. The sound represented by "ir-" is the short "i" sound as in "sir", while "relapsable" has three syllables, starting with a short "e" sound as in "pet" and then followed by "la" and "səbl" which are pronounced as they are spelled.
The word "irrelapsable" is derived from the Latin word "irrelapsus", which is a combination of the prefix "ir" meaning "not", and "relapsus" meaning "to fall back" or "to relapse". The Latin term implies something that cannot relapse, fail, or fall back into a previous state or condition. Over time, the word was adopted into English with the same meaning, ultimately becoming "irrelapsable".