In palude rana viridis sedet, et lacerta prope saxum quieta iacet.

Here in means in / on in the sense of location, so it takes the ablative: in palude = in the swamp / marsh.

A very important Latin rule is:

• in + ablative = location → in, on
• in + accusative = motion toward → into, onto

So:

• in palude = in the swamp
• in paludem = into the swamp

That is why you see palude, not an accusative form.

Because palus is the nominative singular form, the one you usually find in a dictionary.

After in with location, Latin needs the ablative singular, and the ablative of palus, paludis is palude.

So the forms here are:

• palus = nominative singular
• palude = ablative singular

English does not change nouns this way, so this is a very common thing for learners to notice.

Because prope is a preposition that regularly takes the accusative.

So:

• prope saxum = near the rock

This is just something you learn with the preposition. Not every accusative after a preposition means motion. For example:

• in + accusative often suggests motion
• prope + accusative simply means near

So saxum is accusative because prope requires it.

Both rana and lacerta are in the nominative singular, which is the normal case for the subject of a sentence.

Also, the verbs are both third-person singular:

• sedet = he/she/it sits
• iacet = he/she/it lies

So the structure is:

• rana viridis sedet = the green frog sits
• lacerta ... quieta iacet = the quiet/still lizard lies

Latin relies much more on case endings than on word order, so you identify the subject by its form, not just by its position.

Viridis is a third-declension adjective, and in the nominative singular its masculine and feminine forms are the same:

• masculine: viridis
• feminine: viridis
• neuter: viride

So even though rana is feminine, viridis is still the correct form.

It does agree with rana in:

• gender: feminine
• number: singular
• case: nominative

The ending just does not change to -a the way a first/second-declension adjective would.

Because it agrees with lacerta, which is a feminine singular nominative noun.

So:

• lacerta = feminine singular nominative
• quieta = feminine singular nominative

This is standard Latin adjective agreement: adjectives match the nouns they describe in gender, number, and case.

Unlike viridis, quieta is from the type of adjective whose feminine nominative singular often ends in -a.

Here quieta is an adjective, not an adverb.

It describes the lizard’s state: the lizard is quiet / still.

So lacerta ... quieta iacet means something like:

• the lizard lies still
• the quiet lizard lies

Latin often uses an adjective where English might prefer an adverb or a different phrasing.

If Latin wanted a true adverb, it would use a different form, not quieta.

They are both posture verbs, but they are not the same:

• sedet = sits / is sitting
• iacet = lies / is lying

So the frog is pictured as sitting, while the lizard is pictured as lying.

Latin often likes these more specific posture verbs, where English might sometimes just say is or describe the position less precisely.

Because Latin word order is much more flexible than English word order.

Both of these are normal:

• rana viridis
• viridis rana

And both of these are normal too:

• lacerta quieta
• quieta lacerta

Putting the adjective after the noun is very common and often feels neutral. Latin uses word order more for emphasis and style than for basic grammar.

Classical Latin has no articles.

So rana can mean:

• a frog
• the frog

and lacerta can mean:

• a lizard
• the lizard

Which one you use in English depends on the context. Latin simply does not have separate words equivalent to English a/an and the.

Because the verb ending already tells you the person and number.

Both verbs end in -t, which marks third-person singular:

• sedet = he/she/it sits
• iacet = he/she/it lies

Since the nouns rana and lacerta are already present, Latin does not need an extra pronoun.

In fact, Latin often leaves pronouns out unless they are needed for emphasis or clarity.

Yes. Latin allows a lot of word-order variation because the endings show the grammatical roles.

For example, these would still mean essentially the same thing:

• Rana viridis in palude sedet, et lacerta quieta prope saxum iacet.
• In palude sedet rana viridis, et prope saxum lacerta quieta iacet.

The main meaning stays the same, but the emphasis can shift slightly depending on what is placed first or last.

So when reading Latin, it is important not to assume the sentence works exactly like English word order.