Why don't my text messages get sent successfully on my Samsung Galaxy J5?

[Kiblas]

Why doesn't my text messages get sent successfully on my Samsung Galaxy J5

I have a Samsung Galaxy J5. When I text my messages in English, they are sent successfully. But when I send my messages in my language (which are not found in the language settings), it says "Failed MMS". And when I send them in short sentences (5 to 7 words), then they are sent successfully. Please help!

 

[B. Diddy]

Welcome to Android Central! Is your mobile data (3G/4G) turned on? If the messages in your language are being sent as MMS, that requires mobile data, not voice signal or wi-fi.

 

[Kiblas]

Thank you B. Diddy for the welcome! My mobile data is turned off most of the time. Unfortunately our internet here in our country is very limited and we are probably one of the countries who do not have reliable internet access and the cost is very high. So most of time, mobile data is turned off to save money.

But when I send my text message, particularly when it's a long message in my language and the message does not get sent, there is a note on the bottom of the message that says "failed MMS"....what does that mean then if my mobile data is turned off? I'm so irritated when the message doesn't get sent! I can't even copy and paste it to resend it again! So I either have to send smaller messages (which costs more), or I just get tired of sending the message and wait until I go to a regular phone to place a call.

Please Help!