Я вижу разницу.

Because разницу is in the accusative case, not the nominative.

In this sentence, разницу is the direct object of вижу (I see), so Russian changes the noun form.

• Nominative: разница = difference
• Accusative: разницу = difference (as the thing being seen)

For many feminine nouns ending in -а, the accusative singular changes to -у:

• книга → книгу
• машина → машину
• разница → разницу

So:

• разница = the difference (subject form)
• вижу разницу = I see the difference (object form)

Видеть is the infinitive, meaning to see.
Вижу is the first person singular present-tense form, meaning I see.

So:

• видеть = to see
• я вижу = I see

Russian verbs change form depending on the person:

• я вижу = I see
• ты видишь = you see
• он/она видит = he/she sees
• мы видим = we see
• вы видите = you see
• они видят = they see

This is just the normal conjugated form needed after я.

Yes, you can say Вижу разницу without я.

Russian often drops subject pronouns when they are clear from the verb ending. Since вижу already means I see, я is not always necessary.

Compare:

• Я вижу разницу. = I see the difference.
• Вижу разницу. = I see the difference.

Including я can sound:

• more explicit
• more contrastive
• slightly more emphatic

For example, if you want to stress I (and maybe not someone else), я is useful.

The most neutral word order is:

• Я вижу разницу.

That is similar to English subject + verb + object.

But Russian word order is more flexible than English, because case endings show grammatical roles. So other orders are possible:

• Разницу я вижу. = The difference, I see.
• Я разницу вижу. = I do see the difference.

These versions change the emphasis, not the core meaning.

In most beginner situations, Я вижу разницу is the safest and most neutral order.

The stress is:

• ви́жу
• ра́зницу

So the full sentence is pronounced roughly like:

• Я ви́жу ра́зницу.

A few pronunciation notes:

• ж sounds like the s in measure
• я sounds like ya
• unstressed vowels in Russian are often reduced a bit in natural speech

A rough English-style approximation would be:

• ya VEE-zhu RAZ-ni-tsu

Not perfect, but useful as a starting point.

This is a very common question.

In Russian:

• видеть = to see
• смотреть = to look / to watch

So:

• Я вижу разницу. = I see the difference.
• Я смотрю... would mean I am looking at something / watching something.

Видеть is about perception: something is visible to you, or you notice it.
Смотреть is about directing your eyes intentionally.

Examples:

• Я вижу дом. = I see a house.
• Я смотрю на дом. = I am looking at the house.

So for see the difference, Russian uses видеть, not смотреть.

Вижу comes from видеть, which is imperfective.

Here that is normal, because Я вижу разницу usually means something like:

• I see the difference.
• I can tell the difference.
• I understand the distinction.

It describes a present state or ongoing ability.

The perfective partner is usually увидеть:

• Я увидел разницу. = I saw / noticed the difference.

So the contrast is roughly:

• Я вижу разницу. = I see the difference / I can see it now
• Я увидел разницу. = I noticed the difference / I came to see it

This is not just tense; it is also about aspect:

• imperfective = process, state, general seeing
• perfective = completed result, noticing something

Yes. Russian has no articles, so разницу can correspond to either:

• a difference
• the difference

Context tells you which one is meant.

So Я вижу разницу could mean:

• I see a difference.
• I see the difference.

In many contexts, English would naturally translate it as the difference, but Russian itself does not mark that directly with an article.

Yes. Very often it does.

Although видеть literally means to see, it can also mean something like:

• to notice
• to understand
• to recognize

So Я вижу разницу can mean not only I visually see a difference, but also:

• I understand the distinction.
• I can tell the difference.

This is similar to English, where I see can also mean I understand.

Because разницу is the direct object of the verb вижу.

In Russian, direct objects usually do not need a preposition. The case ending does the grammatical work.

So:

• Я вижу разницу. = I see the difference.

No extra word like to, at, or on is needed.

By contrast, some verbs do require prepositions, but видеть with a direct object normally does not.

Yes, but the nuance is a bit different.

• разница = difference
• отличие = distinction / difference

Both are possible, but Я вижу разницу is very common and natural.

Very roughly:

• разница often sounds more everyday and general
• отличие can sound a bit more formal or analytical in some contexts

So for a basic sentence, Я вижу разницу is an excellent, natural choice.

Yes, very natural.

A Russian speaker could use Я вижу разницу in many situations, for example:

• comparing two versions of something
• noticing improvement
• understanding an important distinction
• reacting to a contrast someone is explaining

It is a short, standard, idiomatic sentence and a good model for learning both:

• first-person verb conjugation
• accusative case with feminine nouns