subitement v. soudainement

[alan gould]

any difference between them?  are both frequently used?  Tx

[Chantal Savignat]

I think the difference is very very very little.

I think subitement means more "fast" (and unexpected) and soudainement means  more "unexpected" (and fast)

But it's not really obvious.

Yes the both are commonly used. Some words are used with one or the other.  "il est mort subitement" . we don't say "il est mort soudainement".

[alan gould]

i first learned "tout a coup" so i was surprised when i encountered recently the other two.  

[alan gould]

the italian word "subito" means "immediately."  maybe that sheds some light

[alan gould]

i would also add that in english, i think "suddenly" connotes more that something arose unexpectedly, "out of the blue" 

"i suddenly realized"... versus "i immediately realized" or "i was walking down the street when all of a sudden i heard a loud noise."  the emphasis is more on the unexpected occurrence than the immediacy i would say.