歳, 人, 匹 — Japanese Counters and Their Sound Change Rules

In English, "three years old," "five people," "two cats" — the numbers don't change pronunciation when paired with counters. Japanese is different: when a number meets a counter, the pronunciation often "mutates." In this lesson, we'll learn three of the most common counters: 歳 (age), 人 (people), and 匹 (animals), while mastering the core sound change patterns.

歳 (さい): Counting Age

歳 is used to express age. Most readings are regular, but a few numbers undergo sound changes.

The key ones to circle are 1, 8, and 10 — they gain a double consonant (geminate) っ:

• 一歳 → いっさい (not いちさい)
• 八歳 → はっさい (not はちさい)
• 十歳 → じゅっさい (not じゅうさい)

What about double-digit ages?

For teens, twenties, etc., just combine the tens digit with the ones digit. Sound changes only apply to the ones digit:

Note: 20 years old has a special reading: はたち. This is a fixed expression, not にじゅっさい.

To ask someone's age: 何歳ですか。 (なんさいですか) = How old are you?

人 (にん): Counting People

The 人 counter is even trickier — the first two numbers have completely irregular readings that must be memorized.

The must-remember ones:

• 一人 = ひとり (not いちにん)
• 二人 = ふたり (not ににん)
• 四人 = よにん (not しにん — しにん sounds like "dead person" 死人, which Japanese speakers avoid!)

In practice

家族は何人ですか。 → How many people are in your family?

六人です。 → Six people.

You can also pair it with います (to exist/have):

学生は二十人います。 → There are twenty students.

匹 (ひき): Counting Animals

匹 is used for small animals (cats, dogs, fish, etc.) and has the most complex sound changes — because ひ belongs to the は-row (は・ひ・ふ・へ・ほ), and certain numbers trigger chain reactions.

The Pattern

It looks like a lot, but there's a clear system:

1, 6, 8, 10 → geminate っ + semi-voiced ぴ (ひき → っぴき) 3, 何 → voiced び (ひき → びき) Everything else → no change, stays ひき

Memory trick: "1-6-8-10" go semi-voiced (ぴ), "3" and "何" go voiced (び), the rest stay unchanged.

This pattern is universal!

Good news — all counters starting with は-row sounds follow this same pattern. When you later learn:

• 本 (ほん): counting long, thin objects (pens, bottles, umbrellas)
• 杯 (はい): counting cups

Their sound changes at 1, 6, 8, 10 are exactly the same:

So learn one pattern, and you've got all は-row counters covered.

Using with います

When counting animals, います (to exist/to have) is typically used:

Note: The third sentence uses the particle が — this is a common pairing with います. The pattern "(person) は (thing) が います" means "someone has something." We'll cover が in detail later.

Summary

• 歳: 1, 8, 10 have geminate sound changes (いっさい, はっさい, じゅっさい); 20 has the special reading はたち
• 人: 一人 (ひとり) and 二人 (ふたり) are irregular; 四人 is read よにん (not しにん)
• 匹: は-row counter sound change pattern — 1/6/8/10 get geminate + semi-voiced, 3/何 get voiced
• The same は-row pattern applies to 本, 杯, and other counters
• Use います with people/animal counters to express "there are" or "have"

Practice

Q1. How do you say "I'm 18 years old this year" in Japanese?

Q2. How do you say "I have two cats" in Japanese?

Q3. 一匹 (いっぴき), 六匹 (ろっぴき), 八匹 (はっぴき) — what do their sound changes have in common?