Он, видимо, забыл.

Because видимо here is an introductory word: it comments on the whole statement rather than acting as a normal part of the sentence.

So Он, видимо, забыл. means something like He apparently forgot / He seems to have forgotten.

The commas show that видимо is parenthetical. In writing, this is the standard punctuation.

A useful comparison:

• Он, видимо, забыл. = Apparently, he forgot.
• If a similar-looking word is used as a regular adverb in another sentence, punctuation may change depending on meaning.

Here видимо means apparently, evidently, or it seems.

It suggests the speaker is inferring this, not stating it as a confirmed fact. In other words, the speaker probably has some evidence or context, but is not 100% certain.

So the tone is not the same as a flat statement Он забыл. = He forgot.

Instead, Он, видимо, забыл. adds uncertainty or deduction:

• Apparently he forgot
• He seems to have forgotten
• It looks like he forgot

Not quite. This is an important distinction.

In Он, видимо, забыл., видимо is an introductory word meaning apparently.

But in other contexts, a related form can feel closer to visibly or in a visible way. In modern usage, though, when learners see видимо set off by commas, it is usually the parenthetical apparently meaning.

So the commas help you interpret it correctly:

• Он, видимо, забыл. = Apparently, he forgot.

Because Russian uses the past tense here to express that the forgetting happened already.

забыл is the past tense form of забыть.

Russian past tense agrees with gender and number:

• он забыл = he forgot
• она забыла = she forgot
• оно забыло = it forgot
• они забыли = they forgot

So забыл specifically tells you the subject is masculine singular, which matches он.

Because забыл comes from the perfective verb забыть, while забывал comes from the imperfective verb забывать.

Here the perfective form is natural because it refers to a completed event/result:

• Он, видимо, забыл. = He apparently forgot / He seems to have forgotten

This means the forgetting has happened, and now that result matters.

By contrast, забывал would usually suggest repeated or habitual forgetting, or forgetting in some ongoing/background sense:

• Он часто забывал. = He often forgot.

So for a single inferred instance, забыл is the normal choice.

Yes. Russian does not have a separate tense built exactly like the English present perfect.

So Он забыл can often correspond to either:

• He forgot
• He has forgotten

The exact English translation depends on context.

In Он, видимо, забыл., English often sounds most natural as:

• He seems to have forgotten
• Apparently, he forgot
• Apparently, he has forgotten

Yes, you often could, if the subject is already clear from context.

Russian frequently omits subject pronouns when they are understood. So in conversation:

• Видимо, забыл. = Apparently, he forgot / Apparently, I forgot / etc., depending on context

But он is included here for clarity or emphasis:

• to make clear that it was he
• to contrast him with someone else
• or simply because the speaker chose to say it explicitly

So both are possible, but Он, видимо, забыл. is clearer in isolation.

Yes, fairly flexible.

Russian word order is more flexible than English, and moving видимо changes emphasis more than basic meaning.

Possible variants:

• Он, видимо, забыл.
• Видимо, он забыл.
• Он забыл, видимо.

All can mean roughly Apparently, he forgot, but the rhythm and focus differ.

The version you have is very natural. It puts он first and inserts видимо as a comment before the main verb.

It is generally neutral and quite common.

It works in both speech and writing. Depending on context, near-equivalents include:

• по-видимому = a bit more bookish or formal in some contexts
• кажется = it seems, often a little more personal or subjective
• похоже = it looks like, often more conversational

So Он, видимо, забыл. is a very normal and natural sentence.

A helpful pronunciation guide is:

Он, ви́димо, забыл.

Approximate stress:

• он
• ВИ-ди-мо
• за-БЫЛ

The commas also reflect a small pause in speech around видимо, because it is parenthetical.

It can, depending on tone and context.

By itself, Он, видимо, забыл. is fairly neutral: the speaker is simply making an inference.

But in real conversation, intonation can make it sound:

• neutral: Apparently he forgot
• mildly critical: Looks like he forgot
• ironic or annoyed: Well, apparently he forgot

So the grammar itself is neutral, but the tone can shift the feeling a lot.

Common natural translations include:

• Apparently, he forgot.
• He apparently forgot.
• He seems to have forgotten.
• Evidently, he forgot.
• It seems he forgot.

The best choice depends on context, but Apparently, he forgot and He seems to have forgotten are especially natural.