Hei, olen uusi työntekijä.

Yes. Hei is a very common Finnish greeting and usually corresponds to Hi or Hello in English.

A few useful notes:

• Hei is neutral and common in everyday speech.
• You can use it in both fairly casual and normal polite situations.
• In very informal speech, people also say Moi.

So Hei, olen uusi työntekijä. is a natural way to begin introducing yourself.

Because Finnish often leaves out the subject pronoun when the verb ending already shows who the subject is.

• olen = I am
• The ending -n tells you the subject is I

So:

• Minä olen uusi työntekijä. = I am a new employee.
• Olen uusi työntekijä. = also I am a new employee.

Both are correct, but omitting minä is very common and natural.

Olen is the 1st person singular present tense of the verb olla, which means to be.

A few forms of olla in the present tense are:

• minä olen = I am
• sinä olet = you are
• hän on = he/she is
• me olemme = we are
• te olette = you are
• he ovat = they are

So in this sentence, olen simply means am.

Because uusi is an adjective meaning new, and here it is describing työntekijä in the basic dictionary form, called the nominative.

In Finnish, adjectives usually match the noun they describe in case and number.

Here:

• uusi = new
• työntekijä = employee

Both are singular and nominative, so the phrase is:

• uusi työntekijä = a new employee

If the case changed, both words would usually change too. For example:

• uuden työntekijän = of a new employee / a new employee (object in some contexts)

Työntekijä literally breaks down into parts related to work and doer/agent.

It comes from:

• työ = work
• työn = of work / work’s (the genitive form used in compounds and derivations)
• tekijä = doer, maker, person who does something

So työntekijä is literally something like worker or person who works, and in normal English it is often translated as employee or worker, depending on context.

Because Finnish does not have articles like English a, an, and the.

So:

• uusi työntekijä can mean a new employee
• In some contexts it might also be understood more generally as the new employee, depending on the situation

Finnish relies on context much more than English does for this.

Yes. Olen uusi työntekijä is completely correct on its own. It simply means I am a new employee.

Hei is just the greeting at the beginning.

So:

• Hei, olen uusi työntekijä. = Hi, I’m a new employee.
• Olen uusi työntekijä. = I’m a new employee.

Finnish word order is somewhat flexible, but this neutral order is very natural.

A rough guide is:

työntekijä ≈ tyoen-teki-ya, but English does not have exact matches for some Finnish sounds.

A few pronunciation points:

• y in Finnish is not like English y in yes. It is a vowel, somewhat like the u in French tu or German ü.
• ö is also a front vowel, somewhat like German ö.
• j in Finnish sounds like English y in yes.
• The stress is on the first syllable: TYÖNtekijä

You do not need a perfect accent immediately; the important thing is to notice that Finnish spelling is very consistent.

Because Hei is being used as a separate greeting before the main sentence.

So the structure is:

• Hei, = Hi,
• olen uusi työntekijä. = I am a new employee.

This punctuation is natural in written Finnish, just as in English you might write:

• Hi, I’m a new employee.

Yes, you can. It is grammatically correct.

The difference is mainly emphasis:

• Olen uusi työntekijä. = neutral, natural everyday Finnish
• Minä olen uusi työntekijä. = I am a new employee, with a bit more emphasis on I

Native speakers often include pronouns when:

• they want contrast or emphasis
• they want to be especially clear
• they are speaking carefully

So for a simple introduction, Olen uusi työntekijä sounds very natural.

It is a very good general word, but not always the only choice.

Common related words:

• työntekijä = employee / worker
• uusi työntekijä = new employee
• toimistotyöntekijä = office worker
• henkilökunta = staff
• työkaveri = coworker

In many situations, työntekijä sounds perfectly normal. But depending on the workplace, job title, or context, a more specific word might be used.