一个汉语的母语者可能不是汉族，可能是中国土生土长的朝鲜人，蒙古人，其他各个国家、各个民族的人，只要他她一出生就生长在汉语的环境里，他就是汉语的母语者，但是汉语的原语民严格说只是汉族，再比如，世界各地的人定居美国后他们的孩子一出生就说英语，他们都是英语的母语者，但是英语的原语民却是英国人

母语者 in this case is better for sure! 原语民 as 원어민 in Korean, is not equivalent with 'native speaker' semantically. Having said that, when we want to say ' I am xx native speaker' in Mandarin, we tend to use 'my native language is XX' format. - > 我的母语是英语（'my mother tongue is English' =I am English native speaker, instead of 我是英语母语者) Hope this helps.

"母语者" is better. However, we don't often say "母语者" directly. For the sentence like "I'm a mandarin native speaker/I'm native speaker of mandarin", the common translation would be “我的母语是中文”。Just for your reference. :-)

we dont really use the word'原语民'

Neither "母语者" nor "原语民" exist in Mandarin. Some words just can't be translated directly from English to Mandarin. In English, we can add "er" at the end of some words become the noun. It means the people doing that action. But in Chinese, we don't have this grammar. We don't say "I'm a native speaker," we say "My mother language is.." That in Mandarin is: 我的母语是普通话.