Speech = droppping ts

[simonec]

Help it seems to be overnight that my DD, almost 4 1/2, seems to have lost the ability to say t. It's for everything: water, butter, better, nothing.
Her speech has always been pretty good up to now, but I don't know if I should automatically correct her, or will this make it an issue. We are currently going through a boundary testing phase.

My DD does this, if I pretend not to hear/understand what she says she usually says the word properly when she repeats it.