Þessi beyging ruglar mig stundum.

Þessi means this.

It appears as þessi because it has to agree with beyging in gender, number, and case.

• beyging is feminine
• singular
• nominative (because it is the subject of the sentence)

So the correct form is:

• þessi beyging = this inflection

By contrast, þetta is used with neuter singular nouns.

Beyging usually means inflection, declension, or conjugation, depending on context.

In language-learning contexts, it refers to the way words change form, for example:

• noun case endings
• adjective endings
• verb conjugations

So in this sentence, Þessi beyging ruglar mig stundum, beyging means something like this inflection pattern or this grammatical form.

Ruglar is the present tense form of the verb að rugla.

Here it means confuses or mixes up.

So:

• að rugla = to confuse / to mix up
• ruglar = confuses

The sentence structure is:

• Þessi beyging = subject
• ruglar = verb
• mig = object
• stundum = sometimes

So literally: This inflection confuses me sometimes.

Because mig is the object form of ég.

Compare:

• ég = I
• mig = me

In this sentence, the inflection is doing the confusing, and me is the person affected:

• Þessi beyging ruglar mig = This inflection confuses me

So Icelandic uses mig because the verb takes an object here.

That is because að rugla in this meaning takes the accusative object, not the dative.

So the verb pattern is:

• rugla einhvern = confuse someone

Therefore:

• mig = accusative of ég
• not mér, which is dative

This is something learners often have to memorize with Icelandic verbs: many verbs require a specific case for their object.

Stundum means sometimes.

It is an adverb, and adverbs in Icelandic can often move around somewhat depending on style and emphasis. In this sentence, putting it at the end is completely natural:

• Þessi beyging ruglar mig stundum.

You may also see adverbs in other positions in Icelandic, but this placement is very common and easy to understand.

Mostly yes, in this sentence.

The order is:

• Þessi beyging = This inflection
• ruglar = confuses
• mig = me
• stundum = sometimes

So it follows a very English-like pattern:

• subject + verb + object + adverb

However, Icelandic word order can be more flexible than English in many contexts, especially because case endings help show what each word is doing.

There are two main clues:

1. Position
   It comes before the verb in a normal statement, which often signals the subject.

2. Case form
   Þessi beyging is in the nominative, the usual case for the subject.

Meanwhile, mig is in the accusative, which strongly suggests it is the object.

So:

• Þessi beyging = the thing doing the confusing
• mig = the person being confused

The past tense of að rugla here is ruglaði.

So:

• Þessi beyging ruglaði mig stundum.
• This inflection confused me sometimes.

The rest of the sentence stays the same.

Yes. Beyging is a broad grammar term for how words change form.

Depending on context, it can refer to:

• noun declension
• adjective inflection
• pronoun forms
• verb conjugation

So if a learner says Þessi beyging ruglar mig stundum, they may be talking about any tricky grammatical pattern that changes according to case, person, number, tense, and so on.

A rough learner-friendly guide is:

• Þessi ≈ THES-si
• beyging ≈ BAY-ying or BAY-ging depending on how carefully you say it
• ruglar ≈ RUG-lar
• mig ≈ mikh or mig with a soft Icelandic g
• stundum ≈ STUN-dum

A few useful notes:

• Þ is like the th in thin
• ey sounds roughly like ay
• Icelandic g is often softer than English learners expect

Exact pronunciation varies a bit, but that should help you recognize and say the sentence.

Yes, but it means something slightly different.

• Þessi beyging ruglar mig stundum = This inflection confuses me sometimes
• Þetta ruglar mig stundum = This confuses me sometimes

So þetta can replace the whole noun phrase if the thing is already understood from context, but it is less specific.