Puer prope rubum accedit, sed mater eum monet ne spinas tangat.

Because prope is a preposition that takes the accusative case.

So:

• prope = near / near to
• rubus = bush
• rubum = bush in the accusative singular

In Latin, many prepositions require a specific case after them. Here, prope rubum means near the bush.

Accedit is:

• 3rd person singular
• present tense
• active voice
• from accedo, accedere = to approach, to come near

So puer ... accedit means the boy approaches or the boy comes near.

Literally, it has the sense of moving toward something.

Because moneo usually takes a direct object: the person being warned or advised.

So:

• mater = the mother
• eum = him
• monet = warns / advises

Thus mater eum monet means the mother warns him.

Latin often makes this relationship very clear by using the accusative for the person affected by the warning.

Because eum is the accusative singular masculine form of the pronoun is, ea, id.

Here it is the direct object of monet, so the accusative is required.

Forms to compare:

• is = he or that man/boy as a subject
• eum = him as an object

So:

• is monet = he warns
• mater eum monet = the mother warns him

Here ne introduces a negative command, warning, or purpose-like clause after monet.

So mater eum monet ne spinas tangat means something like:

• the mother warns him not to touch the thorns
• the mother tells him not to touch the thorns

This is a very common Latin construction:

• moneo / impero / persuadeo / caveo and similar verbs
• followed by ne
  • subjunctive
• to express not to do something

So ne here means that ... not or more naturally in English, not to.

Because after monet ne, Latin normally uses the subjunctive.

Tangat is:

• 3rd person singular
• present subjunctive
• from tango, tangere = to touch

This is not a simple statement of fact like he touches. Instead, it is part of a clause expressing what the mother is warning him not to do.

So:

• tangit = he touches (indicative, plain statement)
• tangat = that he touch / he should touch (subjunctive)

With ne, it becomes:

• ne tangat = that he not touch / not to touch

Because spinas is the direct object of tangat.

So:

• spina = thorn
• spinas = thorns in the accusative plural

He is being warned not to touch the thorns, so the thing being touched goes into the accusative case.

Because the verb agrees with its subject, not with its object.

In ne spinas tangat, the subject is still he—the boy understood from earlier in the sentence. That subject is singular, so the verb is singular too.

• implied subject = he
• spinas = object, plural
• therefore tangat = singular

English works the same way:

• he touches the thorns
• not he touch the thorns just because thorns is plural

Yes. Prope is important.

• accedit already means approaches or comes near
• but prope rubum specifies the place: near the bush

Latin often uses both a verb of motion and a phrase showing the place approached. So the sentence emphasizes that the boy is moving into the area near the bush.

A natural English translation might be:

• The boy approaches the bush
• or The boy comes near the bush

Even though English may not always translate every word separately, the Latin includes both accedit and prope rubum.

Latin word order is more flexible than English because case endings show the grammatical roles.

This order is perfectly normal:

• sed = but
• mater = subject
• eum = object
• monet = main verb
• ne spinas tangat = clause explaining the warning

Latin often places important words for emphasis or rhythm rather than following a fixed English-style pattern.

So this could also appear in other orders and still mean the same basic thing, as long as the endings remain clear.

Yes. Moneo can mean several related things, such as:

• warn
• advise
• remind
• instruct

In this sentence, because of ne spinas tangat, the sense is clearly a warning or caution:

• the mother warns him not to touch the thorns

But in another context, moneo might be better translated as advise or remind.