jQuery to get text of first span of every li

I am trying to get the first value of span under different li elements. My HTML markup is as follows...

<div class="mipartrel">
    <div class="k-multiselect-wrap k-floatwrap">
        <ul role="listbox" unselectable="on" class="k-reset">
            <li class="k-button">
                <span>bat</span>
                <span class="k-icon k-delete">delete</span>
            </li>
            <li class="k-button">
                <span>ball</span>
                <span class="k-icon k-delete">delete</span>
            </li>
        </ul>
    </div>
</div>

I used the following jQuery code to get the text of all the span elements...

var getdata=$('.mipartrel ul li span').first().text();

...but I am only getting the value "bat". I need each and every value from the first span of every li.