Reading is the only hobby I can speak of.
讀書是我唯一值得一提的愛好。
Obviously I can't speak for other people, but certainly no one I know would entertain the idea.
我顯然不能代表其他人的意見，可是我認識的人當中肯定沒有人會有這樣的想法。
I can't speak English fluently as I am out of practice.
我不能流利地說英語，因為我已荒疏了。
I can't speak fluently among strangers.
和陌生人在一起，我講話不流暢。
I think you can always speak english.
我認為你總可以說英語嘛。