A little training
The non-natives I work with sometimes use the plural trainings in their English. On the web it’s not hard to find this form being used in various languages:
Su partner global en Trainings de Management
Les trainings sont données dans plusieurs locaux a Paris centre
I trainings hanno l’obiettivo di condividere conoscenze
Trainings für Teamentwicklung und Kommunikation
But for most native speakers of English, training is an uncountable noun. The Cambridge online dictionary defines it as ‘the process of learning the skills you need to do a particular job or activity’ (my emphasis). This makes it less likely to be used as a plural.
For a countable unit of training, English prefers such compound nouns as training course, training day or training session:
So the phrase a little training, used by a native speaker, would mean ‘some training’ and not ‘a small-scale training course/session’.
Further notes
Actually, there are quite a lot of instances on the web of trainings used by natives. The majority seem to be from those who offer such ‘trainings’ professionally; a substantial proportion are in the area of ‘new age’ practice/therapy. Among the general population, however, I think it’s fair to say that training is uncountable.