Портной пришил заплатку.

• Портной = tailor
• пришил = sewed on / attached by sewing

And заплатку is the object:

• заплатка = patch
• заплатку = patch in the accusative case

So the sentence is literally something like The tailor sewed on a patch.

Because портной is a masculine noun with a stem pattern that happens to end in -ой in the nominative singular.

This is normal in Russian. Not all masculine nouns end in a consonant. Some end in:

• a consonant, like стол
• -й, like герой
• and some adjective-like occupational words such as портной

So портной is still masculine singular, even though the ending may look unusual at first.

Because заплатка is the direct object of the verb, so it goes into the accusative case.

Its dictionary form is:

• заплатка = nominative singular

But after a transitive verb like пришить (to sew on / attach by sewing), the direct object changes:

• пришить заплатку = to sew on a patch

This is a very common pattern for feminine nouns ending in -а:

• nominative: -а
• accusative: -у

For example:

• книга → книгу
• рубашка → рубашку
• заплатка → заплатку

Пришил is the past tense, masculine singular form of the verb пришить.

Breakdown:

• infinitive: пришить
• past masculine: пришил
• past feminine: пришила
• past neuter: пришило
• past plural: пришили

Since портной is masculine singular, the verb is also masculine singular:

• Портной пришил заплатку.

That is the normal way Russian forms the past tense.

Very roughly:

• take the infinitive stem
• add past marker -л
• then add gender/number endings where needed

Examples:

• делать → делал
• читать → читал
• пришить → пришил

In the masculine singular, there is usually no extra ending after -л:

• пришил

But other forms do add endings:

• пришила
• пришило
• пришили

This is a question of aspect, which is very important in Russian.

• шить = imperfective
  Focuses on the process, repeated action, or ongoing action: was sewing, sewed, used to sew
• пришить = perfective
  Focuses on the completed result: sewed on, finished attaching by sewing

So:

• Портной шил заплатку. = The tailor was sewing a patch / sewed a patch (process-focused, less natural without context)
• Портной пришил заплатку. = The tailor sewed on the patch / attached the patch by sewing (completed action)

In this sentence, пришил tells you the patch was successfully attached.

In this verb, при- gives the idea of attaching something to something else.

Compare:

• шить = to sew
• пришить = to sew on, sew onto, attach by sewing

So пришить заплатку is not just to sew in a general sense. It means to sew the patch onto something.

Often Russian prefixes add a spatial or result-oriented meaning, and here при- helps create that idea of fixing something onto another thing.

The stress is:

• портнОй
• пришИл
• заплАтку

So the whole sentence is pronounced approximately:

part-NOY pree-SHEEL zap-LAT-koo

A couple of pronunciation notes:

• Unstressed о is reduced and often sounds closer to a.
• Unstressed и can sound shorter or less clear than in careful dictionary pronunciation.

Yes. Russian word order is flexible because case endings show grammatical roles.

The neutral order here is:

• Портной пришил заплатку.

But you could also hear:

• Заплатку пришил портной.
• Пришил портной заплатку.

These alternatives change the focus or emphasis, not the core meaning.

For example:

• Заплатку пришил портной may emphasize the patch
• Пришил портной заплатку may sound more narrative or stylistically marked

For a learner, the original order is the safest and most neutral.

Russian often leaves that unstated if it is obvious from context.

So Портной пришил заплатку is a complete sentence, even though English often wants something like:

• The tailor sewed a patch onto the jacket
• The tailor sewed on a patch

If you want to say what it was attached to, Russian can add it:

• Портной пришил заплатку к куртке. = The tailor sewed a patch onto the jacket.

So the basic sentence is complete, but the location or target can be added if needed.

Because Russian has no articles.

So заплатку can mean:

• a patch
• the patch

And портной can mean:

• a tailor
• the tailor

Which one is meant depends on context.

That is normal in Russian, and learners have to get used to meaning being carried by context rather than by articles.