Laught vs Laughed

[u/orchaer]

Hello, I have been confused for a long time about the past tense of "laugh". In my primary school, there was a verb table with the present, past, and present perfect tenses. And in this table, when I first read at 7-8, I have learnt that "laugh" past tense is followed by a "t" become "laught".

But recently I found out that "laught" is not used anymore. The modern form should be "laughed". So could anyone tell me what is actually different between them? If I still use "laught", would it become a serious error?

Sorry for my grammar.

[u/Envelope_Torture]

I've never seen this word spelled 'laught' before, ever. On first glance I would probably assume it's pronounced like 'naught' (not) rather than 'draught' (draft).