Hello! I think there is something romantic in the usage of music terms (legato and staccato) in linguistics.
As for staccato pronounciation it means an abrupt way of pronounciation
As for legato it's a smooth way.
But to my mind to say that pronounciation of some language is abrupt and of other is smooth is mere a subjective opinion. For me, for instance, German pronounciation is not at all abrupt. Well, they use glottal stop when the word begins with a vowel and to somebody it may seem to sound abrupt, but I don't feel that way.