The spelling of the word "fixt up on" can be a bit confusing. In IPA phonetic transcription, it would be /fɪkst ʌp ɒn/. The "fixt" part is a variant of "fixed" where the "-ed" ending has been dropped. "Up" is pronounced with a schwa sound (ʌ) instead of a clear "uh" sound, as some might expect. And "on" is pronounced with the short "o" sound (ɒ) found in words like "lot" or "hot". Altogether, "fixt up on" means to improve or enhance something.