JS if.statement between a split string

Hey everyone :) How can I place if statements between a split string? Obviously I can make it like that:

if(lang == 'eng'){
  var a_string = 'hello';
}else if(lang == 'ger'){
  var a_string = 'hallo';
}

but that's too long for some situations. What came in my mind was the following:

var lang = (e.g. 'ger' or 'eng');

var a_string = 'h' + if(lang == 'eng'){'e'}else if(lang == 'ger'){'a'} + 'llo';

Is there a way to write if statements between a split string?