Ég reyndi að grípa glasið, en það datt samt.

Because reyna normally takes an infinitive with að when it means to try to do something.

• ég reyndi að grípa = I tried to catch
• að here is the infinitive marker, similar to English to

So the structure is:

• reyna að + infinitive
• reyndi að grípa
• reyndi að hlaupa
• reyndi að hjálpa

Glasið is the noun glas with the definite article attached.

• glas = a glass
• glasið = the glass

Icelandic usually puts the on the end of the noun instead of using a separate word.

Also, this form is accusative singular definite, because grípa takes a direct object here:

• grípa eitthvað = catch something

So:

• glas → base noun
• glasið → the glass as the object of the verb

Because grípa usually takes a direct object, and that object is in the accusative case.

Here the thing being caught is the glass, so Icelandic puts it in the accusative:

• að grípa glasið = to catch the glass

This is something learners often need to memorize with verbs: which case they govern.

Because glas is a neuter noun in Icelandic, and pronouns must agree with the noun’s grammatical gender.

• glas = neuter
• so the matching pronoun is það = it

Even though English also says it, in Icelandic this is tied to grammatical gender:

• masculine noun → hann
• feminine noun → hún
• neuter noun → það

So það refers back to glasið.

Datt is the past tense of the verb detta, which means to fall.

The basic forms are:

• detta = to fall
• datt = fell
• dottið = fallen

So:

• það datt = it fell

This is a strong verb, so the vowel changes instead of just adding a regular ending.

Both detta and falla can relate to falling, but they are not always used in exactly the same way.

In everyday Icelandic:

• detta is very common for fall/drop suddenly
• falla can be more formal or used in some different contexts

For a glass slipping and falling, detta is very natural.

So það datt sounds like the normal everyday way to say it fell in this context.

Here samt means still, anyway, or all the same.

In this sentence it shows that the second part happened despite the first:

• Ég reyndi að grípa glasið, en það datt samt.
• I tried to catch the glass, but it still fell.

So samt adds the idea of in spite of that.

That position is very natural in Icelandic. Short adverbs like samt are often placed later in the clause, especially after the verb.

• það datt samt = it still fell / it fell anyway

You may also see adverbs in other positions depending on emphasis, but this version sounds very normal.

Putting samt here gives a smooth, conversational feel.

Because en means but, and after it you simply begin a new clause.

The second clause is:

• það datt samt

This has normal clause order:

• subject: það
• verb: datt
• adverb: samt

Icelandic often has verb-second word order, but in a simple clause like this, subject + verb is exactly what you expect.

Reyndi is the past tense singular form of reyna.

With many Icelandic verbs in the past tense, 1st person singular and 3rd person singular are the same:

• ég reyndi = I tried
• hann/hún/það reyndi = he/she/it tried

So the subject pronoun ég tells you it means I tried.

Yes, in English that is a natural way to express the same idea, and it matches the Icelandic well.

But grammatically, Icelandic is using the structure:

• reyna að + infinitive
• literally: try to catch

So while the English translation may vary, the Icelandic construction is straightforwardly tried to catch.

Without samt, the sentence would be:

• Ég reyndi að grípa glasið, en það datt.

That means:

• I tried to catch the glass, but it fell.

This is perfectly grammatical, but samt adds an extra nuance:

• despite my trying, it fell anyway
• it still fell

So samt makes the contrast stronger.

Yes. Grípa often means catch, grab, or snatch, depending on context.

In this sentence, because the glass is falling or about to fall, English usually prefers:

• catch the glass

If the context were different, grab the glass could also be possible. The Icelandic verb itself is flexible enough to cover both ideas.

Because the sentence has two main clauses joined by en:

• Ég reyndi að grípa glasið
• það datt samt

Using a comma before en is standard here and helps mark the contrast between the two parts:

• I tried to catch the glass, but it still fell.

So the punctuation works much like it does in English.