i guess it could be classed as similar to html it is a more interactive languange than just html for instance it can be used for pop up messages controlling right clicks on pages etc i believe there is a tutorial on w3schools ... have a look into it.
ok the reason the majority of people use dreamweaver to design webpages is because it makes everything simpler for instance if you want to place text in a certain location using html code you would have to do something roughly along the lines of,
"""this is extremely rough its been about 2 years since ive manually coded tables lol"""
<td style="vertical-align:middle;">Text Here </td>
<td style="vertical-align:middle;">More Text Here<td>
where as in dreamweaver you would simply click on layout mode draw a new table where you would like the text and then draw a layou cell where you wish the text to start and eend.
also it just brings a user friendly interface to web site design, again adding an image that when clicked will take you to goolgle.co.uk in code would have to write
<a href="http://www.google.co.uk"><img src="images/google.jpg" alt="google" align="center" valign="top"> </a>
but in dreamweaver goto insert button the media object select image then it will ask you to browse to the image in a windows style way which is very easy then it will ask you for alternative text and if you would like it to link to anywhere, then it will add the image to a default place and you can drag it to exactly where you want it on the page