LanguageController.cs

using UnityEngine;
using DarkTonic.MasterAudio;

public class LanguageController: MonoBehaviour {

	public static SystemLanguage _selectedLanguage;

	void Awake () {
		_selectedLanguage = GetLanguage();
	}

	public static void SetLanguage (string button) {
		if (button != "") {
			switch(button) {
				case "English_US":
					_selectedLanguage = SystemLanguage.English;
					MasterAudio.DynamicLanguage = SystemLanguage.English;
			        break;

				case "English_UK":
					_selectedLanguage = SystemLanguage.Unknown;
					MasterAudio.DynamicLanguage = SystemLanguage.Unknown;
			        break;

				case "French":
					_selectedLanguage = SystemLanguage.French;
					MasterAudio.DynamicLanguage = SystemLanguage.French;
			        break;

				case "Spanish":
					_selectedLanguage = SystemLanguage.Spanish;
					MasterAudio.DynamicLanguage = SystemLanguage.Spanish;
			        break;

				case "German":
					_selectedLanguage = SystemLanguage.German;
					MasterAudio.DynamicLanguage = SystemLanguage.German;
			        break;

				default:
					break;
			}
		}
	}

	public static SystemLanguage GetLanguage () {
		_selectedLanguage = MasterAudio.DynamicLanguage;

		return _selectedLanguage;
	}
}

MainMenuEvents.cs

using UnityEngine;
using DarkTonic.MasterAudio;
using UnityEngine.UI;

public class MainMenuEvents : MonoBehaviour {

	float _voiceOverVolume;
	float _backgroundVolume;
	public Toggle[] _aryOfToggles;

	public float VoiceOverVolume {
		get {
			return _voiceOverVolume;
		}
		set {
			_voiceOverVolume = value;
		}
	}
	public float BackgroundVolume {
		get {
			return _backgroundVolume;
		}
		set {
			_backgroundVolume = value;
		}
	}

	void Start () {
		SetActiveToggle();
	}

	public void OnRelease(string button) {
		LanguageController.SetLanguage(button);
//	    LanguageController.PlayCurrentLanguage(button);
	}

	public void VoiceOverSlider (float value) {	
		VoiceOverVolume = value;
		PersistentAudioSettings.SetBusVolume("Voiceovers", VoiceOverVolume);
	}

	public void BackgroundSoundSlider (float value) {
		BackgroundVolume = value;
		PersistentAudioSettings.SetBusVolume("SFX", BackgroundVolume);
	}

	void SetActiveToggle () {
		switch (LanguageController.GetLanguage())
		{
			case SystemLanguage.English:
				_aryOfToggles[0].isOn = true;
				break;
			case SystemLanguage.Unknown:
				_aryOfToggles[1].isOn = true;
				break;
			case SystemLanguage.French:
				_aryOfToggles[2].isOn = true;
				break;
			case SystemLanguage.Spanish:
				_aryOfToggles[3].isOn = true;
				break;
			case SystemLanguage.German:
				_aryOfToggles[4].isOn = true;
				break;
			default:
				break;
		}
	}
}