I see words like
stayin' , livin' , 'eck , 'our.
The first word I saw in the song, Staying alive.
I've never seen 'eck or 'our to be fair, but stayin' and livin' are informal writings born from relaxed pronunciation and the tendency to want to write things the same way we hear them (especially these last 15 years).
This is the same phenomenon behind the apparition of gonna, gotta, wanna, kinda, lemme in written discussions: these are not grammatically acceptable but can be used in very informal discussions.
'eck , 'our.
are used by native English writers (i.e. in literature) to imitate certain local accents (in Britain), where people tend not to pronounce the starting 'h' in words at all.