There are two types of adjectives in modern Japanese: な- and い-adjectives. Both are descriptive and modify nouns. They describe nouns and form predicates differently.
The い-adjectives (形容詞, けいようし) are fairly simple creatures. Any い-adjective will end on an "い" in it's basic form and they behave very regularly. The only problem in differentiating between い- and な-adjectives comes from the fact that some な-adjectives also end on "い" (e.g. きれい and ゆうめい) or a syllable in the い-row (e.g. げんき).
Watch and Listen 
Listen to the teacher read the following phrases, or click here (needs soundbite) to listen on your computer.
|Adjective||Noun||Adjective and noun|
|a game, a videogame||ゲーム|
|high, tall, expensive||高い||たかい|
When they stand alone, い-adjectives don't take the copula, but when modifying nouns, they do. Otherwise they don't change.