Space requirements (with respect to foriegn languages)

My site/code/database is developed primarily for the english language.
I've had people from "The Far East" add content to my site using their
native language, and it is displaying properly in the site.
But Im a bit concerned about the number of characters these languages use.
For example, I've had someone enter ->
chinese testing　中文

It is saved in the database as ->
chinese testing　中文

Now, forgive my ignorance, but I have no idea what the additional
chinese characters mean, but from the values in the database, Im
assuming that it amounts to 3 characters.
But if Im correct that those are 3 characters, it is
using up 24 characters in a column.

My concern is that what if I were to limit a column to say 25 "english"
characters, and a chinese fellow, comes by and hypothetically says
"Hello World" in chinese and goes over the limit of the column, the data
will be truncated.

Is there anything that can be done to overcome this shortcoming?

Im currently using PostgreSQL 7.4.2, using SQL_ASCII as the database
characterset, FreeBSD 4.10, php 4.3.6.

Thanks for any advise you can provide...