英文文法唔明白

First of all both sentences should use "speaking", because here the the word speaking act as a noun.

1) Anyone who is interested in the english speaking group should sign "his/her" or just "their" name here = "anyone" means anybody in a group. For example, a teacher may ask this to a whole class of people.

2) Those who is interested in the english speaking group should sign "his / her" or just "their" name here = those means certain people in a group. For example, a teacher may ask" who is interest in a english speaking group?" and 5 out of 10 people raise their hands, then the teacher may use the above sentence to ask them to sign up. Those meaning those 5 people.

got it????

anyone沒有指明誰 但是 those有指明誰