Here's the thing, I do think subtitles can pull you out of the experience and lead to less immersion with the gaming world, because you read lines instead of focusing on gestures and facial expressions. Still, subtitles are a must in some cases. When English is not your first language, subtitles can help, especially when strong accents are part of the experience. There are also games like Bastion where even with very good English it can become tough to follow the narrator AND fight battles at the same time. As fluent as some of us are in second languages, I think we tend to understand our mother tongue even passively without too much concentration and effort, while we have to actively listen to foreign languages.