The Univision Deportes channels (1524/1539) do not have a second audio track, just the primary Spanish one, at least on FiOS at this moment. Local UniMas affiliates may or may not have secondary tracks, it depends on who runs the station in your local area and how they have their equipment configured. Here in Dallas, the UniMas station is owned and operated by Univision and has a secondary track (didn't catch the MLS game so I don't know if it was in English). The NYC and LA stations are also O&Os and should presumably have a second track. The affiliates in Boston, DC/Baltimore, and Tampa are run by Entravision, and it wouldn't surprise me if they don't.