How can legato notes be played staccato? Gardener Read (in his handbook Music Notation) explains, “When [staccato] marks are combined with slurs, the result is more psychological that actual. That is, the combination suggests a quality of sound, rather than indicating it exactly” (269).
Look at the music example above, the first bar shows the notated version while the second bar shows how you’d play it. You can see that the staccato dots do create a break between each note. However, you’ll play the breaks lazily, more like sixteenth note rests than true staccato.
The example below gives another common use of the notation. Bar 1 shows a slur leading into a staccato dot. Bar 2 shows you how it would be played. Basically, you’d play the notes legato right into the F note. However, the F will be shortened to a true staccato length.
In other words, the staccato in the second example will have more “bounce” than you’d use while performing the first example. So, yes, legato notes can be played staccato… ish. What you might think of as semi-staccato.