The consonants used in Japanese are k, g, s, z, t, d, n, h, f, b, p, m, y, r, and w; and they are pronounced the same as you would in English, except for the following:
•r - this is like the Spanish r, so ri should sound like a lightly pronounced dee
•d - because r sounds like a light d, d has a more distinct d sound
Japanese consonants are not thought of as having their own sound, except for n. All of the others always appear combined with a vowel, with the vowel coming after the consonant, like ka, for example. This combination of one consonant and one vowel makes only one "letter" in the Japanese alphabet, and to the Japanese mind represents only one sound. This is a very important point to remember when studying Japanese.
There are also a few letters which have combined consonants like shi, chi, and tsu. Again, each of these look like 3 letters to us, but they are each viewed as one in Japanese.
As with vowels, consonants also have doubles. Doubled consonants are found in compound words like ippun, which means "one minute." The difficulty in pronouncing the double consonant is that there's nothing to pronounce; it's just the trick of "holding" the pronunciation so that the "time value" of the double is recognized, just like with the vowels. When pronouncing ippun, you should be giving equal time to the 4 syllables: i-p-pu-n, with the second syllable being just a silent rest and preparation to pronounce the third. This will be barely noticed during normal speech, but it is important. Doubles not pronounced correctly will be noticed by native listeners. When said correctly, ippun will be heard as "eep-poon," not "ee-poon."
