The mobile phone I'm using at the moment is really slow so I'd like to change it.
The cellphone I'm using at the moment is slow to respond so I'd like to get a new one.
My phone is really slow so I want to get a new one.
「私が使っている携帯の動作が遅いので携帯を変えたい」= The mobile phone I'm using at the moment is really slow so I'd like to change it. / The cellphone I'm using at the moment is slow to respond so I'd like to get a new one. / My phone is really slow so I want to get a new one.
ボキャブラリー
mobile phone/cellphone/phone = 携帯
using at the moment = 今使っている
is really slow = 動作が遅い
I'd like to change it/ I'd like to get a new one / I want a new one = 携帯を変えたい(直訳:新しい携帯が欲しい)
「現在使用中の〜は〜です」という日本語は「the ~ I'm using at the moment is ~」という英語になります。