To speak foul language or not, it is your call. (Ref: 《評論》Make sense of a phrase, 補充)
Is the above sentence a case of "dangling modifier"?
Wiki's definition of a dangling modifier:
A dangling modifier is an ambiguous grammatical construct whereby a grammatical modifier could be misinterpreted as being associated with a word other than the one intended, or with no particular word at all.
Example:
Walking down Main Street, the trees were beautiful.
(Ref: http://en.wikipedia.org/wiki/Dangling_modifier)