Почему не работает событие play()?

//Deer sounds 
let deer1 = new Audio('sounds/deer1.mp3'); 
let deer2 = new Audio('sounds/deer2.mp3'); 
let deer3 = new Audio('sounds/deer3.mp3'); 
//Fox sounds 
let fox1 = new Audio('sounds/fox1.mp3'); 
let fox2 = new Audio('sounds/fox2.mp3'); 
let fox3 = new Audio('sounds/fox3.mp3'); 
//Voice random selection 
function randomVoice() { 
    let rand = 1 + Math.random() * (4 - 1); 
    return Math.floor(rand); 
} 
//playingNow - воспроизводится ли звук 
let playingNow = false; 
//При нажатии на кнопку воспроизведения звука 
//Определяем на какую именно кнопу нажали (currentAnimal) 
//Рандомно выбираем номер звука 1-3 (voiceNumber) 
$('.voice-btn').click(function () { 
    let currentAnimal = $(this).attr('id'); 
    let voiceNumber = randomVoice(); 
    if (!playingNow){ 
        switch (voiceNumber) { 
            case 1: 
                playVoice(currentAnimal + '1'); 
                break; 
            case 2: 
                playVoice(currentAnimal + '2'); 
                break; 
            case 3: 
                playVoice(currentAnimal + '3'); 
                break; 
        } 
        playingNow = true; 
    } 
    //Воспроизводит выбранный выше звук 
    function playVoice(voice) { 
        voice.play(); 
    } 
    //Если один из звуков завершился 
    //разрешаем воспроизводить другой 
    (currentAnimal + '1').onended = function() { 
        playingNow = false 
    }; 
    (currentAnimal + '2').onended = function() { 
        playingNow = false 
    }; 
    (currentAnimal + '3').onended = function() { 
        playingNow = false 
    }; 
});

.voice-btn{ 
  background: #000; 
  color: #fff; 
  padding: 20px; 
  margin: 5px 0 
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script> 
<div class="voice-btn" id="deer">Олень</div> 
<div class="voice-btn" id="fox">Лиса</div>