I did record my 17-month old D's progress for what its worth.
At 12 months old she was speaking a dozen words of English and a dozen words of Swedish.
(Her mother mainly speaks Swedish to her I speak mainly English).
At 15 months old her vocabulary was uncountable (unless you specify a certain subject).
For example, on birds she would say jackdaw, crow, duck, owl (and for the correct species)
In comparison the other kids of similar age in her creche were struggling to say "birdie".
She was also using verbs (one word sentences).
This month she is using 2 word sentences correctly.
She's attempting to count (both languages) and to recite abcs.
4 days ago I started her on that Titzer reading dvd course to see what happens.
She seems to love it so far.