Whatever training is given there should always be a
permanent concern about the naturalness and spontaneity of
everyday speech rather than an artificial sound production for the
sake of preserving a “correct” pronunciation.
This is, in fact, a crucial issue, since if too much care is
demanded from the student, this may turn out to be an
undesirable blockage to another more important factor, namely,
fluency. Perhaps, and even worse, if over-careful pronunciation
habits are developed, this will certainly cause difficulties for the
oral comprehension, as the students will expect to hear sounds,
words and utterances the way they personally produce them.
G.A. Chauvet. Improve Your Pronunciation. Brasília:
Editora Universidade de Brasília, 2005 (adapted).