Code:

cat := catalog.NewBuilder()

_ = cat.Set(language.Russian, "Hello World!", catalog.String("Привет Мир!"))
_ = cat.Set(language.Slovak, "Hello World!", catalog.String("Ahoj Svet!"))
_ = cat.Set(language.Hebrew, "Hello World!", catalog.String("שלום עולם"))
_ = cat.Set(language.Russian, "Hello {name}!", catalog.String("Привет %[1]s!"))
_ = cat.Set(language.English, "Hello {name}!", catalog.String("Hello %[1]s!"))
_ = cat.Set(language.English, "There are {bikes} bikes per household.", catalog.String("There are %v bikes per household."))
_ = cat.Set(language.Russian, "There are {bikes} bikes per household.", catalog.String("В каждом доме есть %v велосипеда."))
_ = cat.Set(language.English, "You are {minute} minute(s) late.",
    plural.Selectf(1, "",
        "=0", "You're on time.",
        plural.One, "You are %v minute late.",
        plural.Other, "You are %v minutes late."))
_ = cat.Set(language.Russian, "You are {minute} minute(s) late.",
    plural.Selectf(1, "",
        "=1", "Вы опоздали на одну минуту.",
        "=0", "Вы вовремя.",
        plural.One, "Вы опоздали на %v минуту.",
        plural.Few, "Вы опоздали на %v минуты.",
        plural.Other, "Вы опоздали на %v минут.",
    ),
)
_ = cat.Set(language.Russian, "It costs {cost}.",
    catalog.String("Это стоит %.2f."))
_ = cat.Set(language.English, "It costs {cost}.",
    catalog.String("It costs %.2f."))

provider := gotext.NewProvider(gotext.WithCatalog(translation.DefaultDomain, cat))

trans := translation.New(language.Russian, provider)
ctx := context.Background()
// context with language
heCtx := translation.WithLanguage(ctx, language.Make("he"))

fmt.Println(trans.Trans(ctx, "Hello World!"))
fmt.Println(trans.Trans(ctx, "Hello World!", translation.WithLocale("en")))
fmt.Println(trans.Trans(ctx, "Hello World!", translation.WithLocale("sk")))
fmt.Println(trans.Trans(heCtx, "Hello World!"))

fmt.Println(trans.Trans(ctx, "Hello {name}!", translation.WithArgs("Andrey")))

fmt.Println(trans.Trans(ctx, "You are {minute} minute(s) late.", translation.WithNumber("minute", 1)))
fmt.Println(trans.Trans(ctx, "You are {minute} minute(s) late.", translation.WithNumber("minute", 0)))
fmt.Println(trans.Trans(ctx, "You are {minute} minute(s) late.", translation.WithNumber("minute", 101)))
fmt.Println(trans.Trans(ctx, "You are {minute} minute(s) late.", translation.WithArgs(123456.78)))
fmt.Println(trans.Trans(ctx, "You are {minute} minute(s) late.", translation.WithArgs(50)))
fmt.Println(trans.Trans(ctx, "You are {minute} minute(s) late.", translation.WithArgs(1), translation.WithLocale("en")))
fmt.Println(trans.Trans(ctx, "You are {minute} minute(s) late.", translation.WithArgs(33), translation.WithLocale("en")))

fmt.Println(trans.Trans(ctx, "There are {bikes} bikes per household.", translation.WithNumber("bikes", 1.2)))
fmt.Println(trans.Trans(ctx, "There are {bikes} bikes per household.", translation.WithNumber("bikes", 1.2), translation.WithLocale("en")))

fmt.Println(trans.Trans(ctx, "It costs {cost}.",
    translation.WithCurrency("cost", 12.0101, arg.WithCurrencyISO("rub"), arg.WithCurrencyFormat(arg.CurrencyFormatSymbol))))
fmt.Println(trans.Trans(ctx, "It costs {cost}.",
    translation.WithCurrency("cost", 15.0, arg.WithCurrencyISO("HKD"), arg.WithCurrencyFormat(arg.CurrencyFormatSymbol)),
    translation.WithLocale("en")))

Output:

Привет Мир!
Hello World!
Ahoj Svet!
שלום עולם
Привет Andrey!
Вы опоздали на одну минуту.
Вы вовремя.
Вы опоздали на 101 минуту.
Вы опоздали на 123 456,78 минут.
Вы опоздали на 50 минут.
You are 1 minute late.
You are 33 minutes late.
В каждом доме есть 1,2 велосипеда.
There are 1.2 bikes per household.
Это стоит ₽ 12.0101.
It costs HK$ 15.