Any reconstruction of Ancient Greek needs to take into account how the sounds later developed towards Modern Greek, and how these changes could have occurred. In general, the changes between the reconstructed Ancient Greek and Modern Greek are assumed to be unproblematic in this respect by historical linguists, because all the relevant changes (spirantization, chain-shifts of long vowels towards , loss of initial , restructuring of vowel-length and accentuation systems, etc.) are of types that are cross-linguistically frequently attested and relatively easy to explain.