Messaging Change typing language in messaging app (SMS/MMS)
Create a new message in "Messaging" app or : - keep your finger on the comma (,) until a wheel is displayed , - slide your finger on this wheel or keep your finger out of the keyboard ("Input options" are displayed), - tap on "Languages", - disable "Use system language", then select one or several languages in the list,if needed,* - tap on "← Languages" or "← Google keyboard" or "← Gboard" to come back to the message.
* To switch from a language to another one, touch the spacebar for 2 seconds.