Vas fragile non est tangendum.

Here vas is nominative singular, because it is the subject of est tangendum.

A beginner might wonder whether it could be accusative, since vas is neuter and neuter nominative and accusative often look the same. But in this sentence the structure noun + est + gerundive points to a passive periphrastic, where the noun is the subject.

So:

• vas = nominative singular
• it is the thing being described as not to be touched

Because fragile is the neuter nominative singular form of the adjective fragilis, fragile.

This adjective has forms like:

• masculine/feminine nominative singular: fragilis
• neuter nominative singular: fragile

Since vas is neuter singular, the adjective must agree with it, so Latin uses fragile, not fragilis.

No. Here tangendum is a gerundive, not a gerund.

That matters because:

• a gerund is a verbal noun
• a gerundive is a verbal adjective

In this sentence, tangendum clearly behaves like an adjective, because it agrees with vas in:

• gender: neuter
• number: singular
• case: nominative

So tangendum means something like to be touched or needing to be touched, and with non est it gives the sense must not be touched.

Because the gerundive is an adjective, and adjectives in Latin agree with the nouns they describe.

So:

• vas = neuter singular nominative
• tangendum = neuter singular nominative

This agreement is one of the clearest signs that we are dealing with a gerundive construction.

This is the passive periphrastic construction:

• gerundive + sum
• here: tangendum est

This construction usually expresses:

• necessity
• obligation
• something that ought to be done

So est tangendum does not merely mean is being touched. It means is to be touched, ought to be touched, or must be touched, depending on context.

With non, the sense becomes a prohibition or necessity in the negative: must not be touched.

Because non tangitur and non est tangendum do not mean the same thing.

• non tangitur = is not being touched / does not get touched
• non est tangendum = must not be touched / is not to be touched

So the Latin sentence is not just describing what is happening. It is expressing a rule, instruction, or prohibition.

Here it means to be touched, not touching.

The gerundive normally has a passive sense. Since tango is an active verb meaning touch, its gerundive tangendus, tangenda, tangendum means:

• to be touched
• needing to be touched

In this sentence, the vase is not the one doing the touching. It is the thing that must not receive the action.

Because Latin does not have to state the agent here.

With the passive periphrastic, the person who has the obligation can be expressed in the dative, for example:

• mihi vas tangendum est = I must touch the vase

But if no agent is given, the statement is more general:

• vas fragile non est tangendum = the vase is simply presented as something that must not be touched

That works well for warnings, rules, or notices.

Yes, the word order is flexible.

Latin does not rely on word order as heavily as English does, because the endings show the grammatical relationships. So other arrangements are possible, such as:

• Vas fragile tangendum non est
• Non est vas fragile tangendum

Even so, Vas fragile non est tangendum is a very natural order. It presents:

1. the thing being discussed: vas fragile
2. the negation: non
3. the verbal idea: est tangendum

Yes. Vas is a broader word than the English word vase.

Depending on context, it can mean:

• vessel
• container
• jar
• vase

So the exact English word depends on what sort of object is meant in the situation. Grammatically, though, the sentence works the same way no matter which English noun is chosen.