Complex sentence: Some of the pre-Indo-European languages are attested only as linguistic substrates in Indo-European languages; however, some others (like Etruscan, Minoan, Iberian etc.) are also attested from inscriptions.
Split into simpler sentences: Some of the pre-Indo-European languages are attested only as linguistic substrates in Indo-European languages. A few others (such as Etruscan, Minoan, Iberian, etc.) are also attested from inscriptions.