You need to install any of the malayalam unicode font to read or write malayalam , commonly used unicode malayalam font is AnjaliOldLipi True Type Font . Please following the instructions to install unicode malayalam in your system.
There was no common malayalam ascii structure for the old fonts. so each vendors use different malayalam fonts with different keyboard layouts. this makes difficult with malayalam users as they need to install each malayalam font from different websites like malayala manoram (manoram.ttf) mathrubhumi.ttf etc..
Unicode font is international