Thanks, Bryan. That pretty much clear things up. Although I must say, lately the usage of the word "ialah" is becoming more obsolete. Even local newspaper and tv shows tend to use "adalah" for noun phrases instead of "ialah".

Hi Ayyash! "ialah" is followed by a noun or phrasal noun only, whereas "adalah" can be followed by adjectives or verbs. Example: Saya ialah seorang guru. (I am a teacher) "seorang guru" = a teacher = noun Baju ini adalah* sangat mahal. (This shirt is very expensive) "sangat mahal" = very expensive = adjective * "Baju ini sangat mahal", which omits the word "adalah" is grammatically correct too. I hope this helps. Cheers, and have a great day!