<style type="text/css">
p.speech
{
	position: relative;
	width: 200px;
	height: 100px;
	text-align: center;
	line-height: 100px;
	background-color: #fff;
	border: 8px solid #666;
	-webkit-border-radius: 30px;
	-moz-border-radius: 30px;
	border-radius: 30px;
	-webkit-box-shadow: 2px 2px 4px #888;
	-moz-box-shadow: 2px 2px 4px #888;
	box-shadow: 2px 2px 4px #888;
}
p.speech:before
{
	content: ' ';
	position: absolute;
	width: 0;
	height: 0;
	left: 30px;
	top: 100px;
	border: 25px solid;
	border-color: #666 transparent transparent #666;
}
p.speech:after
{
	content: ' ';
	position: absolute;
	width: 0;
	height: 0;
	left: 38px;
	top: 100px;
	border: 15px solid;
	border-color: #fff transparent transparent #fff;
}
</style>
<style type="text/css">
p.thought
{
	position: relative;
	width: 130px;
	height: 100px;
	text-align: center;
	line-height: 100px;
	background-color: #fff;
	border: 8px solid #666;
	-webkit-border-radius: 58px;
	-moz-border-radius: 58px;
	border-radius: 58px;
	-webkit-box-shadow: 2px 2px 4px #888;
	-moz-box-shadow: 2px 2px 4px #888;
	box-shadow: 2px 2px 4px #888;
}

p.thought:before, p.thought:after
{
	left: 10px;
	top: 70px;
	width: 40px;
	height: 40px;
	background-color: #fff;
	border: 8px solid #666;
	-webkit-border-radius: 28px;
	-moz-border-radius: 28px;
	border-radius: 28px;
}

p.thought:after
{
	width: 20px;
	height: 20px;
	left: 5px;
	top: 100px;
	-webkit-border-radius: 18px;
	-moz-border-radius: 18px;
	border-radius: 18px;
}
</style>
</head>

<p class="speech">อิอิ</p>

<p class="thought">คิด</p>

http://ilikepixels.co.uk/bubbler-css-speech-bubble-generator/
http://ilikepixels.co.uk/drop/bubbler/

<div class="speech-bubble">
  <div class="arrow bottom right"></div>
  Thinking....
</div>

.speech-bubble {
    background-color: #f8f8f8;
    border: 1px solid #c8c8c8;
    border-radius: 5px;
    width: 110px;
    text-align: center;
    padding: 20px;
    position: absolute;
}

.speech-bubble {
    background-color: #f8f8f8;
    border: 1px solid #c8c8c8;
    border-radius: 5px;
    width: 110px;
    text-align: center;
    padding: 20px;
    position: absolute;
}

.speech-bubble .arrow {
    border-style: solid;
    position: absolute;
}
 
.bottom {
    border-color: #c8c8c8 transparent transparent transparent;
    border-width: 8px 8px 0px 8px;
    bottom: -8px;
}

.bottom:after {
    border-color: #f8f8f8 transparent transparent transparent;
    border-style: solid;
    border-width: 7px 7px 0px 7px;
    bottom: 1px;
    content: "";
    position: absolute;
    left: -7px;
}

http://cssarrowplease.com/