Why are *suru* and *kuru* the only irregular verbs in the Japanese language?

These two verbs are considered the "grandfathers" of the language, dating back over a thousand years to Old Japanese. Because they are used so frequently in daily life—meaning "to do" and "to come"—they have resisted the natural "smoothing out" process that standardized other verb patterns over time. Their irregularity is a result of being so central to the language that their unique, ancient forms were preserved rather than forced into modern regular boxes.

How does the vowel shifting work for the verb *kuru*?

The verb *kuru* is unique because its stem changes vowels depending on the form being used, moving through the "K" column of the hiragana chart. In its dictionary form, it uses *ku* (*kuru*); in polite or past forms, it shifts to *ki* (*kimasu*, *kita*); and in negative or potential forms, it shifts to *ko* (*konai*, *korareru*). This "musical chairs" with vowels is why it is specifically categorized as a "K-column irregular" verb.

What is the relationship between the verbs *suru* and *dekiru*?

While many learners study them as separate vocabulary words, *dekiru* is actually the potential form of *suru*. Historically, *suru* was so irregular that it did not develop a standard potential conjugation; instead, it borrowed *dekiru* (which originally meant "to come forth" or "to appear") to express the ability to do something. This is also why *dekiru* uses the particle *ga* instead of *o*, as it describes a state of existence or "manifestation" of ability rather than a direct action.

What is "ra-nuki" and why is it used in modern conversation?

"Ra-nuki" refers to the practice of dropping the *ra* syllable from potential verb forms, such as saying *koreru* instead of *korareru*. While traditional grammar rules label this as incorrect, many speakers use it to distinguish between the potential form ("can do") and the passive form ("was done to"), which are otherwise identical for certain verbs. Using "ra-nuki" helps clear up ambiguity in casual speech, though the full form is still required in formal or academic settings.

How is *suru* used to describe physical sensations or traits?

In Japanese, *suru* is used to describe sensations that "arise" or "manifest" spontaneously rather than actions a person actively performs. For example, instead of "having" a headache or "smelling" a scent, a speaker says the headache or smell is "doing" (*zutu ga suru* or *nioi ga suru*). This same logic applies to physical traits, such as "doing blue eyes" (*aoi me o shite iru*), treating these characteristics as states that are currently manifesting.

Japanese irregular verbs: Why suru and kuru are different

39 min

4 abr 2026

Education Communication skill Science

Struggling with Japanese verbs that don't follow the rules? Learn why these two 'rebels' are the key to natural conversation and how to master them.

Mejor cita de Japanese irregular verbs: Why suru and kuru are different

These irregular verbs aren't just random mistakes; they are the flexible joints of the language that have been shaped by the human voice over a thousand years to express how reality manifests and affects us.

Esta lección de audio fue creada por un miembro de la comunidad BeFreed

Pregunta de entrada

Demystifying Japanese irregular verb

Voces del presentador

Eli

Miles

Estilo de aprendizaje

Profundo

Fuentes de conocimiento

Preguntas frecuentes

Creado por exalumnos de la Universidad de Columbia en San Francisco

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"Feels effortless compared to reading. I’ve finished 6 books this month already."

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"BeFreed turned my commute into learning time. 20-min podcasts are perfect for finishing books I never had time for."

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"It is great for me to learn something from the book without reading it."

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@Cashflowbubu

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"Perfect balance between learning and entertainment. Finished ‘Thinking, Fast and Slow’ on my commute this week."

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@Matt, YC alum

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"Reading used to feel like a chore. Now it’s just part of my lifestyle."

@Erin, Investment Banking Associate , NYC

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"Feels effortless compared to reading. I’ve finished 6 books this month already."

@djmikemoore

"BeFreed turned my guilty doomscrolling into something that feels productive and inspiring."

@Pitiful

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"BeFreed turned my commute into learning time. 20-min podcasts are perfect for finishing books I never had time for."

@SofiaP

"BeFreed replaced my podcast queue. Imagine Spotify for books — that’s it. 🙌"

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@Matt, YC alum

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"Reading used to feel like a chore. Now it’s just part of my lifestyle."

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"Feels effortless compared to reading. I’ve finished 6 books this month already."

@djmikemoore

"BeFreed turned my guilty doomscrolling into something that feels productive and inspiring."

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"BeFreed turned my commute into learning time. 20-min podcasts are perfect for finishing books I never had time for."

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"The themed book list podcasts help me connect ideas across authors—like a guided audio journey."

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Japanese irregular verbs: Why suru and kuru are different

39 min

4 abr 2026

Education Communication skill Science

Struggling with Japanese verbs that don't follow the rules? Learn why these two 'rebels' are the key to natural conversation and how to master them.

Mejor cita de Japanese irregular verbs: Why suru and kuru are different

These irregular verbs aren't just random mistakes; they are the flexible joints of the language that have been shaped by the human voice over a thousand years to express how reality manifests and affects us.

Puntos clave

The Power of Two Rebels

0:00

Eli: You know, Miles, I was looking at my Japanese notes this morning and I started wondering—why is it that in a language so famous for its logical, predictable verb patterns, we’re suddenly hit with these "rebels" like *suru* and *kuru*? It feels like they’re just there to trip us up, doesn't it?

0:15

Miles: It’s a great question. Most people assume Japanese is this perfectly rigid system of *u-verbs* and *ru-verbs*, but then these two show up and play by their own rules. But what if they aren't just random mistakes? What if their "irregularity" is actually a clue to how much we use them?

0:32

Eli: Right, like they're so common they've worn down their own edges over time? I mean, *suru* is everywhere, especially when you start attaching it to nouns like *benkyou* to make "study."

0:42

Miles: Exactly. They are the only two truly irregular verbs in the whole language. Let’s explore how these two powerhouses actually work and why mastering them is the real secret to unlocking daily conversation.

The Anatomy of an Irregular Heartbeat

The Mystery of the Shifting Particle

The Ghost in the Machine: Spontaneity and -(r)are-

The "Can-Come" Confusion and the Polite Invitation

When "Doing" Becomes "Being": The Hidden Meanings of Suru

The "Ra-Nuki" Rebellion: A Language in Flux

The Past Tense Trap and the "Done" Delusion

Practical Playbook for the Master Learner

Closing Reflections on the Living Language

Esta lección de audio fue creada por un miembro de la comunidad BeFreed

Pregunta de entrada

Demystifying Japanese irregular verb

Voces del presentador

Eli

Miles

Estilo de aprendizaje

Profundo

Fuentes de conocimiento

Preguntas frecuentes

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Creado por exalumnos de la Universidad de Columbia en San Francisco

BeFreed Reúne a una Comunidad Global de 1,000,000 Mentes Curiosas

Ver más sobre cómo se habla de BeFreed en la web

"Instead of endless scrolling, I just hit play on BeFreed. It saves me so much time."

@Moemenn

"I never knew where to start with nonfiction—BeFreed’s book lists turned into podcasts gave me a clear path."

@Chloe, Solo founder, LA

117

"Perfect balance between learning and entertainment. Finished ‘Thinking, Fast and Slow’ on my commute this week."

@Raaaaaachelw

"Crazy how much I learned while walking the dog. BeFreed = small habits → big gains."

@Matt, YC alum

108

"Reading used to feel like a chore. Now it’s just part of my lifestyle."

@Erin, Investment Banking Associate , NYC

254

"Feels effortless compared to reading. I’ve finished 6 books this month already."

@djmikemoore

"BeFreed turned my guilty doomscrolling into something that feels productive and inspiring."

@Pitiful

4.5K

"BeFreed turned my commute into learning time. 20-min podcasts are perfect for finishing books I never had time for."

@SofiaP

"BeFreed replaced my podcast queue. Imagine Spotify for books — that’s it. 🙌"

@Jaded_Falcon

201

"It is great for me to learn something from the book without reading it."

@OojasSalunke

"The themed book list podcasts help me connect ideas across authors—like a guided audio journey."

@Leo, Law Student, UPenn

483

"Makes me feel smarter every time before going to work"

@Cashflowbubu

Creado por exalumnos de la Universidad de Columbia en San Francisco

BeFreed Reúne a una Comunidad Global de 1,000,000 Mentes Curiosas

Ver más sobre cómo se habla de BeFreed en la web

"Instead of endless scrolling, I just hit play on BeFreed. It saves me so much time."

@Moemenn

"I never knew where to start with nonfiction—BeFreed’s book lists turned into podcasts gave me a clear path."

@Chloe, Solo founder, LA

117

"Perfect balance between learning and entertainment. Finished ‘Thinking, Fast and Slow’ on my commute this week."

@Raaaaaachelw

"Crazy how much I learned while walking the dog. BeFreed = small habits → big gains."

@Matt, YC alum

108

"Reading used to feel like a chore. Now it’s just part of my lifestyle."

@Erin, Investment Banking Associate , NYC

254

"Feels effortless compared to reading. I’ve finished 6 books this month already."

@djmikemoore

"BeFreed turned my guilty doomscrolling into something that feels productive and inspiring."

@Pitiful

4.5K

"BeFreed turned my commute into learning time. 20-min podcasts are perfect for finishing books I never had time for."

@SofiaP

"BeFreed replaced my podcast queue. Imagine Spotify for books — that’s it. 🙌"

@Jaded_Falcon

201

"It is great for me to learn something from the book without reading it."

@OojasSalunke

"The themed book list podcasts help me connect ideas across authors—like a guided audio journey."

@Leo, Law Student, UPenn

483

"Makes me feel smarter every time before going to work"

@Cashflowbubu

"Instead of endless scrolling, I just hit play on BeFreed. It saves me so much time."

@Moemenn

"I never knew where to start with nonfiction—BeFreed’s book lists turned into podcasts gave me a clear path."

@Chloe, Solo founder, LA

117

"Perfect balance between learning and entertainment. Finished ‘Thinking, Fast and Slow’ on my commute this week."

@Raaaaaachelw

"Crazy how much I learned while walking the dog. BeFreed = small habits → big gains."

@Matt, YC alum

108

"Reading used to feel like a chore. Now it’s just part of my lifestyle."

@Erin, Investment Banking Associate , NYC

254

"Feels effortless compared to reading. I’ve finished 6 books this month already."

@djmikemoore

"BeFreed turned my guilty doomscrolling into something that feels productive and inspiring."

@Pitiful

4.5K

"BeFreed turned my commute into learning time. 20-min podcasts are perfect for finishing books I never had time for."

@SofiaP

"BeFreed replaced my podcast queue. Imagine Spotify for books — that’s it. 🙌"

@Jaded_Falcon

201

"It is great for me to learn something from the book without reading it."

@OojasSalunke

"The themed book list podcasts help me connect ideas across authors—like a guided audio journey."

@Leo, Law Student, UPenn

483

"Makes me feel smarter every time before going to work"

@Cashflowbubu

"Instead of endless scrolling, I just hit play on BeFreed. It saves me so much time."

@Moemenn

"I never knew where to start with nonfiction—BeFreed’s book lists turned into podcasts gave me a clear path."

@Chloe, Solo founder, LA

117

"Perfect balance between learning and entertainment. Finished ‘Thinking, Fast and Slow’ on my commute this week."

@Raaaaaachelw

"Crazy how much I learned while walking the dog. BeFreed = small habits → big gains."

@Matt, YC alum

108

"Reading used to feel like a chore. Now it’s just part of my lifestyle."

@Erin, Investment Banking Associate , NYC

254

"Feels effortless compared to reading. I’ve finished 6 books this month already."

@djmikemoore

"BeFreed turned my guilty doomscrolling into something that feels productive and inspiring."

@Pitiful

4.5K

"BeFreed turned my commute into learning time. 20-min podcasts are perfect for finishing books I never had time for."

@SofiaP

"BeFreed replaced my podcast queue. Imagine Spotify for books — that’s it. 🙌"

@Jaded_Falcon

201

"It is great for me to learn something from the book without reading it."

@OojasSalunke

"The themed book list podcasts help me connect ideas across authors—like a guided audio journey."

@Leo, Law Student, UPenn

483

"Makes me feel smarter every time before going to work"

@Cashflowbubu

1.5K Ratings4.7

Comienza tu viaje de aprendizaje, ahora

Japanese irregular verbs: Why suru and kuru are different

Mejor cita de Japanese irregular verbs: Why suru and kuru are different

Esta lección de audio fue creada por un miembro de la comunidad BeFreed

Preguntas frecuentes

Why are suru and kuru the only irregular verbs in the Japanese language?

How does the vowel shifting work for the verb kuru?

What is the relationship between the verbs suru and dekiru?

What is "ra-nuki" and why is it used in modern conversation?

Japanese irregular verbs: Why suru and kuru are different

Mejor cita de Japanese irregular verbs: Why suru and kuru are different

Puntos clave

The Power of Two Rebels

The Anatomy of an Irregular Heartbeat

The Mystery of the Shifting Particle

The Ghost in the Machine: Spontaneity and -(r)are-

The "Can-Come" Confusion and the Polite Invitation

When "Doing" Becomes "Being": The Hidden Meanings of Suru

The "Ra-Nuki" Rebellion: A Language in Flux

The Past Tense Trap and the "Done" Delusion

Practical Playbook for the Master Learner

Closing Reflections on the Living Language

Esta lección de audio fue creada por un miembro de la comunidad BeFreed

Preguntas frecuentes

Why are suru and kuru the only irregular verbs in the Japanese language?

How does the vowel shifting work for the verb kuru?

What is the relationship between the verbs suru and dekiru?

What is "ra-nuki" and why is it used in modern conversation?

Más como esto

Puntos clave

The Power of Two Rebels

The Anatomy of an Irregular Heartbeat

The Mystery of the Shifting Particle

The Ghost in the Machine: Spontaneity and -(r)are-

The "Can-Come" Confusion and the Polite Invitation

When "Doing" Becomes "Being": The Hidden Meanings of Suru

The "Ra-Nuki" Rebellion: A Language in Flux

The Past Tense Trap and the "Done" Delusion

Practical Playbook for the Master Learner

Closing Reflections on the Living Language

Más como esto