mySQL: Query performance with User Defined Functions - mysql

Question

I'm trying to make a multi-language mySQL database.
I was considering using user defined functions to determine which column in a table to read - where different columns will store the different translations - however I was concerned about query performance.
For example, if I wanted to return a list of Cities, and the name of country - with the latter returned in multiple languages. At what point would the below approach impact performance? - as I might do an equivalent on a table with 2-5,000 rows.
Country table structure:
SELECT
`CountryID`,
`Name_English`,
`Name_French`,
`Name_Spanish`
FROM `Country`
WHERE `CountryID` = fCountryID;
City Table Structure:
SELECT
`City`.`CityName` 'City'
,getCountry(1, `City`.`CountryID`) 'Country'
FROM `City`;
Example Function Call:
SELECT
`City`.`CityName` 'City'
,getCountry(1, `City`.`CountryID`) 'Country'
FROM `City`;
Full Function:
delimiter $$
CREATE DEFINER=root#localhost FUNCTION
getCountry(fLanguageID INT, fCountryID SMALLINT)
RETURNS varchar(100) CHARSET utf8 COLLATE utf8_unicode_ci
BEGIN
DECLARE returnCountry VARCHAR(100);
IF (fLanguageID = 1) -- English
THEN
SET returnCountry = (
SELECT `Name_English` FROM `Country`
WHERE `CountryID` = fCountryID
);
ELSEIF (fLanguageID = 2) -- French
THEN
SET returnCountry = (
SELECT `Name_French` FROM `Country`
WHERE `CountryID` = fCountryID
);
ELSEIF (fLanguageID = 3) -- Spanish
THEN
SET returnCountry = (
SELECT `Name_Spanish` FROM `Country`
WHERE `CountryID` = fCountryID
);
END IF;
RETURN returnCountry;
SELECT
`CountryID`,
`Name_English`,
`Name_French`,
`Name_Spanish`
FROM `Country`
WHERE `CountryID` = fCountryID;
SELECT
`City`.`CityName` 'City'
,getCountry(1, `City`.`CountryID`) 'Country'
FROM `City`;
END$$