Can a language disappear?

It rained again today, so all my plans of going for jogging had to be cancelled. So I sat in my room, looking at my laptop. I begin to wonder about the languages in the world, and I recall reading a report in a magazine about how many languages has disappeared. Then I begin to think to myself, can the Malay language disappear? Well, the Malay that we Malaysians speak is rather different from the Indonesian language (though we do understand each other a little bit), and since the Indonesian population is so big, I assume it's going to be there for at least 800-1000 years time.

With Encarta Encyclopedia 2004 as my reference (I used to have Brittanica 2003, but then, Encarta is much more user friendly), I started to research on the ancient languages of the world. There happen to be hundreds, or perhaps thousands of them. But what really interests me is the Semitic language. The Semitic language is divided into 4 groups. In order to make it look simple, I have created the table below.

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North Peripheral Group

Assyro-Babylonian language (also known as Akkadian)
Also known to be the oldest semitic language (spoken between 3000 BC and 400 BC).

North Central Group

Ancient and modern Hebrew.
Ugaritic and Phoenician.
Aramaic - the language of Prophet Isa (Jesus)

South Central Group

Standard Arabic and modern spoken Arabic dialects

South Peripheral Group

South Arabic dialects, now spoken in parts of the southern Arabian Peninsula (and in ancient times by peoples such as the Minaeans and Sabaeans); and the languages of Ethiopia
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Frankly, it never occurred to me that Prophet Isa spoke Aramaic. I really wonder how it sounds. Anyways, after reading further, I found out that Aramaic survives today in Eastern and Western dialects, mostly as the language of Christians living in a few scattered communities in Syria, Lebanon, Turkey, Iraq, and Iran.