because there are many versions, I don't know which version you installed. I have had this problem before, and I did it like this (according to the instructions on the localization steps on the 3dm website)

(In order to avoid problems, it is strongly recommended that you back up the Fallout.ini file first. You can refer to

to find my document (XP and WIN7 have different locations) -My Games-FalloutNV-

* Cancel the read-only property of Fallout.ini

* Open Fallout.ini, search for [Fonts], and replace the following with:

sfontfile _ 1 = texture. Fonts\karl_gb.fnt

sFontFile_2=Textures\Fonts\karl_gb.fnt

sFontFile_3=Textures\Fonts\karl_gb.fnt

sFontFile_4=Textures\Fonts\ karl_gb.fnt

sFontFile_5=Textures\Fonts\fixedsys_kar.fnt

sFontFile_6=Textures\Fonts\karl_gb.fnt

sFontFile_7=Textures\Fonts\ Karl _ gb.fnt

sfontfile _ 8 = textures \ fonts \ Karl _ gb.fnt

sfontfile _ 9 = textures \ fonts \ Karl _ gb.fnt

* Set Fallout.ini as read-only.