How to use special symbols

Are you sure you saved your code with UTF8 encoding? By default VisualStudio uses the Windows-1252 encoding (Western Europe) which is essentially the Latin1 character set as far as i remember. Just make sure you save your code as UTF8 to support the full unicode character set.

For I18n it's generally better to save the used texts into a seperate file. Commonly either some sort of csv, xml or json file which can be read by your game. Personally i would probably use json with my SimpleJSON framework. You can simply structure it like this:

 {
     "English" : {
         "scoreText" : "You scored: {0}",
         "eliminatedEnemy" : "You destroyed {0} {1}",
     },
     "Chinese" : {
         "scoreText" : " ...{0} ...",
         "eliminatedEnemy" : "... {0} {1}",
     }
 }

Now when parsing this text file (of course need to be saved with UTF8 as well) you can simply get the proper language sub object and the proper text like this:

 JSONNode i18n;
 JSONNode currentLang;
 
 void Start()
 {
     i18n = Json.Parse(yourLanguageFileContent);
     currentLang = i18n["Chinese"];
 }

currentLang would now only contain the sub objects for the current selected language. You can use string.Format with the strings i've written in the example. So the "scoreText" requires one parameter which is the score. The "eliminatedEnemy" text requires two parameters, first enemiesDestroyed and second the enemy name ( assuming Hydra is the enemy name?! )

 deathscore.text = string.Format(currentLang["scoreText"].Value, score);
 eliminatedEnemies.text  = string.Format(currentLang["eliminatedEnemy"].Value, enemiesDestroyed, "Hydra");

That way you have completely outsourced the internationalization part. Also when using string.Format you can more easily reuse the same text templates. Keep in mind that you can also simply store enemy names for different languages and look them up equally simple. You can even structure the json to have more sub categories. To translate to a new language, just send a copy of the english template to the translator.