Handling special/foreign language characters in c#

public string ConvertSpecialCharstoForeignChars(string str)
{
string strFormD = str.Normalize(NormalizationForm.FormD);
StringBuilder sbOutput = new StringBuilder();
for (int ich = 0; ich < strFormD.Length; ich++)
{
UnicodeCategory uc = CharUnicodeInfo.GetUnicodeCategory(strFormD[ich]);
if (uc != UnicodeCategory.NonSpacingMark)
{
sbOutput.Append(strFormD[ich]);
}
}
return sbOutput;
}