The correct spelling of the phrase "forgat about" is actually "forgot about." The mistake in spelling likely comes from the way the word is pronounced in some dialects. The phonetic transcription of "forgat" would be /fɔːgæt/, while the correct pronunciation of "forgot" is /fɔːˈɡɒt/. It is important to pay attention to proper spelling and pronunciation in order to effectively communicate in written and spoken language.
The phrase "forgat about" seems to be a variant or colloquial form of the phrase "forgot about". The etymology of "forgot" comes from the Old English word "forgietan", which means "to lose, forget, or neglect". The term is derived from the combination of the Old English word "for-" (meaning "away" or "completely") and "gietan" (meaning "to grasp" or "get hold of"). Over time, "forgietan" evolved into "forgot", leading to the modern phrase "forgot about", which means failing to remember or neglecting something.