Let's consider the titles that he has done or signed up in 2008. Apart from Mulla, almost all the other titles are in English; Crazy Gopalan (earlier it was Crazy Rascals), Moses B. Samuel, Body Guard, Colours, Passenger, Culcutta News, Guinness Gilbert, and Gays: The Story of Two Kundans. Well, the other big film of the year, Twenty: 20, can be omitted from the list since it stars a whole lot of other actors from the Malayalam film industry.
One of the interesting facts is that this phenomenon is recent. Dilip, who started his career in the early 1990"s, had only a few movies with English titles till 2006, e.g. Three Men Army in 1995, Mr. Butler and Joker in 2000, Runway in 2004 and Lion, The Don and Chess in 2006. But from then on, Dilip is continuously signing films with English titles. In 2007, four of his ventures had English titles: Romeo, July 4, Speed Track and Inspector Garud.
Well, the only possible explanation is that maybe producers believe that putting an English name for a Dilip movie helps its collection in the box office. Dilip is one of the most reliable stars in town who can guarantee a hit by his exquisite comedy timing and he definitely has a way with family audiences. Interestingly, most of his films with English titles have done extremely well in the theatres, prompting the producers to follow the trend.