Add language options for ground-to-air communication

There will definitely be three options for dialogue voice

Lock to English / Lock to Chinese / Realistic

"Lock English" means that all airport dialogues will be in English

"Lock Chinese" means that all dialogues at all airports will be in Chinese

Both options are unrealistic but beneficial for players who want to learn English or have limited proficiency in Chinese

The "Realistic" option uses English at foreign airports or incorporates local voiceovers later on, while domestic airports use a mix of Chinese and English