YOU SAID:

My mother is seated next to me manipulating her mobile phone

INTO JAPANESE

母は私の隣に座って携帯電話を操作しています

BACK INTO ENGLISH

My mother is sitting next to me and using her mobile phone.

INTO JAPANESE

母は私の隣に座って携帯電話を使っています。

BACK INTO ENGLISH

My mother is sitting next to me and using her cell phone.

INTO JAPANESE

母は私の隣に座って携帯電話を使っています。

BACK INTO ENGLISH

My mother is sitting next to me and using her cell phone.