如何使用土耳其语和英语进行搜索查询

I want to perform a search which searches for both languages. I am using COLLATE utf8_unicode_ci on my query to perform this action.

For instance I want to search for "ağaç". It doesn't work, plus I get a warning; Warning: COLLATION 'utf8_unicode_ci' is not valid for CHARACTER SET 'latin1' But my character set is not latin1, I am using utf8_turkish_ci

What I basically want to do is both search for "agac" and "ağaç".

Here is my query

$searchQ = "select ".$options.", ".DB_PREFIX."users.name as owner,
MATCH (title,description,tags) AGAINST ('".$searchKey."' IN BOOLEAN MODE) AS relevance,
MATCH (title) AGAINST ('".$searchKey."' IN BOOLEAN MODE) AS title_relevance FROM ".DB_PREFIX."videos LEFT JOIN ".DB_PREFIX."users ON ".DB_PREFIX."videos.user_id = ".DB_PREFIX."users.id 
WHERE MATCH (title,description,tags) AGAINST('".$searchKey."' IN BOOLEAN MODE) AND ".DB_PREFIX."videos.pub > 0 and ".DB_PREFIX."videos.date < now() $interval COLLATE utf8_unicode_ci ORDER by title_relevance DESC,relevance DESC ".this_limit();

Thanks in advance