Here:
http://www.languagetsar.com/belgicisms-how-belgians-speak-french/
the above link wrote:
‘Savoir’ vs ‘Pouvoir’
Another Belgicism, is the use of the verb ‘savoir’ (‘to know’) in place of ‘pouvoir’ (‘to be able’). In the video, you will see an example of where this caused an amusing misunderstanding for me with a Bruxelles barista. If something is not possible, Belgians will frequently say: ‘Je ne sais pas le faire’ which literally translates as ‘I do not know how to do it’. This turn of phrase is peculiar to Belgium. The French would say either: ‘Ce n’est pas possible.’ (‘It is not possible.’) or ‘On ne peut pas le faire.’ (‘We cannot do that.’). In this case, a visitor will find the French version clearer than the Belgian.
well I believe the French "sais" is actually what we mean as "know" in English.
Mais, je parle seulment un peu francais.
And the usual word for "can" is "peux".
Mais, je aussi seulement parle un peu français. Et je ne peux (pas sais
) pas parle la française belgique.