陈红十分聪明刻苦，仅仅半年，就能用英语交谈了

没有错误。。。

你是要翻译么?
有两种翻译方式
1) Chen Hong is very smart hard-working, so she could chat using English in only half a year.

2)The smart and hard-working girl is Chen Hong, she could use English to chat in only half a year.

3)Chen Hong is very clever and hardworking, she is able to communicate by English only in half a year.

这3种说法都是对地~~看看吧,吼吼~~

Chen Hong was very clever and hard working, she took only half a year to converse in English.

在陈红后面加上“学习英语” 变成
陈红学习英语十分刻苦，仅仅半年，就能用英语交谈了。

陈红十分聪明刻苦，仅仅半年，就能用英语交谈了

Chen Hong, a very clever hard, just half a year, will be able to talk in English