Does "i before e except after c" still apply?

yeh, but there are a few other exceptions, like when directly proceeded by a 'gh' making an 'ay' sound:
Weigh
Neighbor

Unless you are a bad speller.

In most cases when you are speaking english.


I don't think it applies in Yiddish or indonesian?

British government spells end of 'i before e' rule
THE ASSOCIATED PRESS
LONDON -- It's a spelling mantra that generations of schoolchildren have learned - "i before e, except after c."
But new British government guidance tells teachers not to pass on the rule to students, because there are too many exceptions.
The "Support For Spelling" document, which is being sent to thousands of primary schools, says the rule "is not worth teaching" because it doesn't account for words like 'sufficient,' 'veil' and 'their.'
Jack Bovill of the Spelling Society, which advocates simplified spelling, said Saturday he agreed with the decision.
But supporters say the ditty has value because it is one of the few language rules that most people remember.
Personally, short of replacing standard English with texting, the language does have too many contradictions and could benefit from refinement.

Not when texting. It seems vowels are optional.

So far.

Assuming the only language you're going for is English, I would say mostly. The English language is infuriating that way - There are always exceptions to every grammatical or spelling rule. This is very annoying to us but it makes learning English really hard for someone who is used to having set rules for things in their native language.