Al Dupres, 54, a stroke survivor from Cardiff is set to take part in the Step Out for Stroke fundraising walk in aid of the Stroke Association at Roath Lake Park at 2pm on 10 June.   Al, BBC Wales’ continuity announcer, was on holiday in Texas last year when he suddenly couldn’t speak coherently.   Al said:   “I couldn’t speak properly for 24 hours which was very worrying as I speak for a living. But I ended up…