What is the largest language family by number of native speakers?

The largest language family by number of native speakers is Indo-European.

Indo-European includes major languages such as English, Spanish, Portuguese, French, German, Russian, Persian, Hindi, Bengali, and Punjabi. Taken together, these languages have more native speakers than any other recognized language family, numbering several billion people worldwide.

The family is spread across Europe and large parts of South and West Asia, with later global expansion through migration, empire, trade, and education. Its major living branches include Germanic, Romance, Slavic, Indo-Iranian, Celtic, Hellenic, Armenian, and Albanian. English and Spanish are Romance and Germanic? No: English belongs to Germanic, while Spanish belongs to Romance.

Indo-European is sometimes confused with the largest family by number of separate languages. Those rankings can differ because scholars classify dialects and language boundaries differently. The question asks about native speakers, for which Indo-European is the standard answer. Sino-Tibetan, Niger-Congo, and Austronesian are also enormous families, but they have fewer native speakers under commonly used classifications.