This paragraph is in English, using the core Latin unicode letters (unicode-range: U+00-FF)
Below this paragraph is a sentence in Greek (unicode-range: U+00-FF) John 1:1
Ἐν ἀρχῇ ἦν ὁ λόγος, καὶ ὁ λόγος ἦν πρὸς τὸν θεόν, καὶ θεὸς ἦν ὁ λόγος.
Below this paragraph is a sentence in Hebrew (unicode-range: U+00-FF) Genesis 1:1
בְּרֵאשִׁ֖ית בָּרָ֣א אֱלֹהִ֑ים אֵ֥ת הַשָּׁמַ֖יִם וְאֵ֥ת הָאָֽרֶץ׃
There are no special classes here. Instead, we load the fonts we want with @font-face, but specify that it only be applied to the specific unicode-range for the langauge. Then we build a font stack which includes these fonts first, then the Latin font we want for the English text.