Compare the following five pairs of characters:

The katakana in the down row have two additional dots at the top right of each character. This changes their pronunciations as shown by the romanizations.

Phonologically, the [g] sound is a voiced [k] sound. Put your hand on your throat and say [k], as in "kuh"; you will feel no vibration. Now, say [g], as in "guh", and notice the vibration. This vibration indicates that the sound is a "voiced sound".

Now  you know  all the [g]-sound characters, i.e. ga, gi, gu, ge and go, by virtue of adding two dots to your already-learned [k] sounds.

Here are a few examples using ガ ギ グ ゲ ゴ.

The same effect, i.e. voicing, occurs by adding two dots to the characters for the [s] sound as well. The [s] sound becomes the [z] sound when voiced. Compare the following five pairs of characters:

Notice that just as シ is neither [shi] nor [si] in English, ジ is neither [ji] nor [zi] in English.

Whether typed ji or zi, the computer will give you ジ.

Now, try reading following words:

ダ ヂ ヅ デ ド da ji zu de do

The same voicing effect occurs with the [t] sound as well, changing [t] to [d]. As you may have noticed, there are neither [ti] nor [tu] sounds in modern Japanese. The sounds for チ and ツ are closer to [chi] and [tsu] respectively. When these two characters are dotted, to make ヂ and ヅ, they actually become the same sounds as ジ ji and ズ zu, respectively. There are neither [di] nor [du] sounds in pure Japanese. (In recent years, however, as more people become familiar with English and other foreign languages, ways to write the [di] and [du] sounds in katakana have been created. They will be introduced later in the Innovative Writing section). 
So, for now we have:

To obtain the characters ヂ and ヅ on the computer, if needed for whatever reason, type "di" and "du", respectively.
Now, you should be able to read the following words:

Try the words above on your PC.



Your PC should support Japanese characters.

バ ビ ブ ベ ボ  ba bi bu be bo

First look at the following five columns:

You might wonder why the [h] sound transforms into the [p] and [b] sounds. This is not from the voicing effect. To convince yourself, you need to know that in the old days   ハ ヒ フ ヘ ホ  was not pronounced ha hi hu he ho, but more like fa fi fu fe fo. The teeth were not used, but the mouth was closed momentarily with the lips. This lip position is the same as that used when pronouncing the [p] sound. This is why a small circle is added to ハ ヒ フ ヘ ホ for pa pi pu pe po, making パ ピ プ ペ ポ . 
Now, try reading the following words.

When [p] is voiced, it becomes [b]; hence, two dots are added to ハ ヒ フ ヘ ホ to mark the ba bi bu be bo sounds, making  バ ビ ブ ベ ボ.
Try reading the following words:

Congratulations, you have now learned all the katakana characters!