From NBC News:

The 1704 “Betts” Stradivari violin was crafted by Antonio Stradivari, an Italian manufacturer of string instruments. Of the estimated 1,000 violins originally crafted by Stradivari, about 650 still exist. New research suggests these instruments mimic the vowel sounds of the female soprano voice.
Virtuosos who describe the singing voice of a violin may be on to something. The great violin makers, such as Stradivari and Guarneri, may have designed violins to mimic the human voice, new research suggests. The research, described in the current issue of Savart Journal, found the violin produced several vowel sounds, including the Italian “i” and “e” sounds and several vowel sounds from French and English.