While you go through all of the hiragana and katakana, along with their accompanying sounds, you'll encounter a handful of characters and symbols that are liable to cause confusion.

Let's look at them...

ー / ー / N/A

Anytime you see the character ー, you should extend the length of the previous vowel by one mora. This is most common when writing katakana.

For example, take the katakana word “art,” which is アート (aato). ア is “a,” and ト is “to.” Then in between we have ー. So we look at the vowel sound that comes just before ー, and we see that it’s the “a” sound, ア. So we double that sound, giving us the three-mora word アート (a + a + to). If you don’t extend your “a” sound one extra mora, then it will sound like you’re saying ato, which means “after; later” (後).

The ー character is extremely common in katakana words. At a guess, I’d say that it shows up in over 10% of them.

When writing in hiragana, it is common to simply rewrite the vowel sound a a second time rather than using ー. So if we have a word like ああ (aa), which is a casual way to say “yeah,” then we write the second “a” sound as あ and not as ー. All of this stuff will start to make sense as you move through the characters.

〜 / 〜 / N/A

～

Like ー, which adds a steady, elongated pronunciation to a vowel, ～ also denotes an elongated pronunciation, but this time it is not steady/flat. It's still pretty difficult for me to catch and produce the differences between these well... but lucky it almost never becomes a barrier to effective communication.

を / ヲ / wo

Though the romaji for this is written as "wo," the pronunciation is actually closer to "o."

Exceptions: は / wa

When は is a part of a word, it's pronounced "ha."

When it is being used as a (topic) particle, however, it's pronounced as "wa." One rare exception where it is a part of a word and still pronounced "wa" is seen below.

(If you don't know what a "(topic) particle" is yet, don't worry about it too much... you'll encounter several explanations throughout your studies.)

つ / ツ / tsu

There isn't anything in particular unique about つ (tsu) itself, other than the fact that it is the only character with a "ts" sound in it. Be careful when you see a small っ, though, as it is not pronounced tsu. We'll talk about that next.

っ / ッ / 促音　[sokuon / gemination marker]

っ

ッ

When we have a little っ before a character, we put an extra little pause before the following consonant. So when 餓鬼（がき // brat; annoying little kid） has a little っ between the が and the き, then it becomes 楽器（がっき // musical instrument）.

餓鬼（がき // brat; annoying little kid）

楽器（がっき // musical instrument）

When it comes it at the end of a word, we make a short, harsh stop at the final vowel.

づ / ヅ / dzu

づ

ヅ

It’s extremely common to pronounce this character the same as ず (zu).

ぢ / ヂ / dzi

ぢ

ヂ

This one is pronounced more or less the same as じ (ji).