أجل

أجل أو نعم كلاهما واحد وهي تستخدم في اللغة العربية الفصحى . حاولي عدم كتابة اللهجات العامية .تعلميها سماعا للضرورة

hi brian , i can learn you arabic if you wana this , ican help u

Hello,that's pretty interesting question, anyway, it's like a delimma , well , نعم or اجل are both correct , like 'yes' and 'yup' and you can use both of them while talking.

i hope that can help you,and if u need any help in Arabic,i'm a native, from Algeria.

Regards

Molto

the answer is very easy:

it's like in English yes and yea

 نعم commes alone =Yes.

أجل is when followed by sentence. e.g: Yes, i did understand.

أجل فهمت

in the other hand, when using "no" for negation:

لا comes alone = No.

كلَّا when followed by sentence. eg: No, I didn't understand.

كلَّا لم أفهم

I hope you understand better now :)