I know the meaning of these words but I don't know the difference between them exactly.
Would you tell me what the difference between these words is? Accent - Dialect - Colloquial.
I would be thankful if you give me some examples in your answer.
Accent is the way you pronounce words and sentences, so [for example] two people both speaking standard British English might speak with different accents because they use a different set of vowels, or even different intonation. You speak a different dialect if your grammar or vocabulary varies significantly from another speaker's. Colloquial refers to expressions that may not be regarded as standard or formal, but are in common use.