I know I should have asked this previously but is "eisiau" pronounced (English phonetics) "eis-i-eye" or eish-eye"? The example given is different when it's the world alone compared to when it's spoken in the sentence.
Si in Welsh usually gives you the 'sh' sound, so 'eisiau' should be 'aye-shy' in its standard pronunciation.
eisiau is one of those words which has a number of pronunciations, so much so that its 'standard' pronunciation is not often heard! /isha/, /isho/, /ishe/ are all common.
With another very common example, the possessives ei, eu are often pronounced simply as /i/.