starOfWords/Assets/Scripts/WordPair.cs

using System;
using System.Reflection;

[Serializable]
public class WordPair
{
    public string tr;
    public string en;
    public string es;
    public string de;
    public string fr;
    public string pt;

    private const string DefaultLang = "en";

    public WordPair(string tr, string en, string es, string de, string fr, string pt)
    {
        this.tr = tr;
        this.en = en;
        this.es = es;
        this.de = de;
        this.fr = fr;
        this.pt = pt;
    }

    public string GetByCode(string code)
    {
        if (string.IsNullOrWhiteSpace(code))
            code = DefaultLang;

        string safe = code.ToLower();

        FieldInfo f = this.GetType().GetField(safe);
        if (f != null)
        {
            string val = f.GetValue(this) as string;
            if (!string.IsNullOrEmpty(val))
                return val;
        }

        return GetByCode(DefaultLang);
    }

    public string Get(string code) => GetByCode(code);
}