Multilingual input
For multilingual, it is a headache to input multiple languages easily on Ubuntu. As you have more languages under your belt, it is increasingly inconvenient to switch input between different languages. I figured that one can use the compose key on Ubuntu to input multiple languages which use Latin script alphabet without changing the input.
Set Right-Ctrl as the compose keyโ
Open the Settings and set Right-Ctrl as the compose key.

Input multiple languages!โ
With the use of the compose key, you can input latin script with different diacritics.
| Input method | Result |
|---|---|
| Right-Ctrl + ~ + n | รฑ |
| Right-Ctrl + , + c | รง |
| Right-Ctrl + ' + a | รก |
| Right-Ctrl + ` + u | รน |
| Right-Ctrl + " + o | รถ |
| Right-Ctrl + ^ + e | รช |
| Right-Ctrl + * + a | รฅ |
You can read the full list from the following page.
https://www.x.org/releases/X11R7.7/doc/libX11/i18n/compose/en_US.UTF-8.html
UK Keyboardโ
I have been to UK for a while. UK Keyboard has a specific alternate character on the keyboard called Alt Gr. You can enable it in Special Character Entry > Alternate Characters Key > Set to Layout Default.