Plerique viatores ob gelu domi manent, sed nostra familia proficiscitur.

Plerique means most or very many. It is an adjective/pronominal word that is usually found in the plural, because it refers to most members of a group.

Here it agrees with viatores:

• plerique = nominative masculine plural
• viatores = nominative masculine plural

So plerique viatores means most travelers.

A learner might expect something simpler like multi viatores (many travelers), but plerique is stronger: it means most rather than just many.

Viatores is nominative plural, because it is the subject of manent.

Its dictionary form is viator, viatoris (traveler).
The nominative plural of this 3rd-declension noun is viatores.

So:

• viatores manent = the travelers stay/remain

Since plerique describes viatores, both are in the same case and number.

Ob is a preposition meaning because of, on account of, or sometimes in view of.

It takes the accusative case, so gelu here is the object of ob:

• ob gelu = because of the frost/cold

A native English speaker may expect a word like because followed by a clause, but Latin often uses a preposition + noun instead:

• ob gelu = because of the frost
• compare English because of the frost

Latin could also use other expressions for cause, but ob + accusative is a very normal one.

Because gelu is a neuter fourth-declension noun.

Its nominative and accusative singular are both gelu, not gelum.

So even though ob takes the accusative, the form is still:

• nominative singular: gelu
• accusative singular: gelu

This can look strange if you are expecting a regular second-declension neuter ending like -um, but gelu belongs to a different declension.

Domi means at home.

It is a special locative form of domus (home, house). The locative is an old case used mainly for place where, especially with words for cities, towns, and a few special nouns such as domus.

So Latin says:

• domi = at home

without needing a preposition like in.

This is one of those forms that learners usually just memorize:

• domi = at home
• compare Romae = at Rome / in Rome

It can mean both. Maneo, manere basically means remain, stay, or continue to be in a place.

So in this sentence, manent is naturally understood as:

• they stay home
• or more literally, they remain at home

Form:

• manent = 3rd person plural present active indicative

It matches the plural subject plerique viatores.

Because familia is a singular noun in Latin.

Even though a family contains several people, Latin treats familia grammatically as one unit, just as English usually does in American English:

• our family is leaving

So:

• nostra = nominative feminine singular
• familia = nominative feminine singular

They agree with each other.

Because its subject is nostra familia, which is singular.

Even though the family has many members in real life, the grammatical subject is still one singular noun:

• familia proficiscitur = the family sets out / departs

So the verb must also be singular:

• proficiscitur = 3rd person singular

Because proficiscor, proficisci is a deponent verb.

Deponent verbs use passive-looking forms but have active meanings.

So:

• proficiscitur looks like a passive form
• but it means he/she/it sets out, departs, leaves

This is very common in Latin and often confuses beginners.
Some common deponent verbs are:

• loquitur = he/she speaks
• sequitur = he/she follows
• proficiscitur = he/she sets out

So in this sentence, nostra familia proficiscitur means our family sets out, not is set out.

It means something like sets out, starts off, departs, or goes on a journey.

Because the subject is a family and the first part of the sentence mentions travelers, the sense is probably:

• our family sets out anyway
• our family leaves
• our family goes off on its journey

So it is not just a vague goes. It has the idea of beginning a journey or departing.

Because sed means but, and it introduces a contrast between two clauses:

• Plerique viatores ob gelu domi manent
• sed nostra familia proficiscitur

The contrast is:

• most travelers stay home because of the frost
• but our family sets out

The comma helps show that contrast clearly. Latin punctuation in ancient manuscripts was not standardized the way modern punctuation is, but in modern printed Latin this comma is perfectly normal.

Latin word order is more flexible than English word order because the endings show each word’s function.

This sentence could be rearranged in various ways without changing the basic meaning, for example:

• Ob gelu plerique viatores domi manent, sed nostra familia proficiscitur.
• Plerique ob gelu viatores domi manent, sed nostra familia proficiscitur.

However, the given order is natural and clear:

• Plerique viatores first introduces the main group
• ob gelu gives the reason
• domi manent finishes the idea
• sed then marks the contrast
• nostra familia proficiscitur gives the surprising opposite action

So the word order is not random; it helps shape emphasis and flow.

Because Latin has no articles like English the and a/an.

So:

• viatores can mean travelers, the travelers, or sometimes some travelers, depending on context
• familia can mean family or the family

In this sentence, English naturally supplies the sense from context:

• most travelers
• our family

This is very normal in Latin. The language usually does not need an article to be clear.

In many contexts, a masculine plural noun in Latin can refer to a mixed group or to people in general.

So viatores here can easily mean travelers in a general sense, not necessarily only male travelers.

A native English speaker may wonder about this because English usually avoids marking gender in nouns like traveler, but Latin often uses the masculine plural as the default for a mixed or unspecified group.