Pls use bm when in east coast.
C how many ppl will understand u

u go to some part in uk and us also sound not like some english u learn in school lah bro.

bahasa pasar is informal bahasa melayu, spoken everywhere outside, not just in pasar.

formal bahasa melayu is use in formal events. just like when u learn other language, like korean and japanese, there are formal and informal version of communicating.

language is always evolving as time goes by. u compare kamus dewan jilid 1 with latest jilid also got many differences.

same with oxford dictionary 1st version with latest version. same goes with all other language around the world. even u talk chinese people nowadays using sia sui. its not even in mandarin dictionary.

malay language. is always standardized. as long you use the malay u learn in school, you can speak malay outside just fine.

bahasa melayu from kelate, ganu, pahang, kedah, penang etc is the localized version of the language. it is accent. u no need to learn those to communicate. just need to adopt. like texas english, irish english, uk english, aussie english canadian english. heck, even english got a lot of accent. u went to talk normal english with rednecks its as if u speak foreign language with them.

dude, nobody accuse u if u cannot speak like kelantanese, terengganu, perak, kedah and so on. u think selangor's malay can speak kelantan slang? sabah slang? U think kelatanese can speak like perak slang?

nobody gonna get angry with u if u cannot speak the slang lah. there states also the local will understand normal malay because they learn the same thing in school. just like china implementing mandarin to whole china as national language. they dont write their bahasa melayu spm paper in bahase kelate with kelate slang to get A.

nobody is going to blame u for speaking malay imperfectly. dont be like the idiot mp who cant even speak bahasa melayu in parlimen and want to cover it up by "practicing his right" to speak in english

Yes, your teacher was good and smart.