function registerAliases(aliasList, { languageName }) {
      if (typeof aliasList === 'string') {
        aliasList = [aliasList];
      }
      aliasList.forEach(alias => { aliases[alias.toLowerCase()] = languageName; });
    }
@param {string|string[]} aliasList - single alias or list of aliases
@param {{languageName: string}} opts