10.04.26: Level 1 (review); introduction to numbers and nominative plurals [i]; video #1

These short videos introduce two closely related ideas in Latin grammar:

[i] How the numbers ūnus, duo, and trēs work

[ii] How nouns form the nominative plural

Together, these topics lay essential foundations for understanding agreement, number, and noun endings in Latin.

Video #1: Numbers 1–3 and 2^nd declension masculine nouns

[1] In Latin, the numbers ūnus (one), duo (two), and trēs (three) change their form depending on the gender of the noun they describe. This means that numbers agree with nouns in gender, just like adjectives do.

[2] Classical Latin has no definite or indefinite article. There is no word for the or a / an. Although ūnus later developed into words such as French un and une, in Classical Latin it means only the numeral “one”, not an article.

[3] Most 2^nd declension nouns ending in -us or -(e)r are masculine (a few exceptions will be discussed later).

Examples:

equus │ horse

gladius │ sword

puer │ boy

vir │ man

liber │ book

Equus can be translated as “horse”, “a horse”, or “the horse”, depending on context. This works in a similar way to Russian, where dom means house / a house / the house, but odin dom means “one house”.

[4] ūnus is used with masculine nouns:

ūnus equus │ one horse

ūnus gladius │ one sword

ūnus puer │ one boy

ūnus vir │ one man

ūnus liber │ one book

[5] duo is used with masculine plural nouns:

duo equī │ two horses

duo gladiī │ two swords

duo puerī │ two boys

duo virī │ two men

duo librī │ two books

[6] trēs is used with masculine plural nouns:

trēs equī │ three horses

trēs gladiī │ three swords

trēs puerī │ three boys

trēs virī │ three men

trēs librī │ three books

[7] 2^nd declension masculine nouns form the nominative plural with -ī.

[a] Nouns ending in -us

-us > -ī

equus > equī (horse > horses)

[b] Nouns ending in -(e)r

-(e)r > -ī

puer > puerī (boy > boys)

vir > virī (man > men)

[c] Some nouns ending in -er lose the -e- before adding -ī (this pattern will be discussed in more detail later.)

liber > librī (book > books)

[8] Practice Sentences

Quot? │ how many?

Quot is indeclinable i.e. it does not change regardless of the gender or case of the noun

Quot equī / puerī / virī sunt in pictūrā? │ How many horses / boys / men are in the picture?

In pictūrā est ūnus equus. │ In the picture (there) is one horse.

In pictūrā sunt duo puerī. │ In the picture (there) are two boys.

In pictūrā sunt trēs virī. │ In the picture (there) are three men.