The spelling of "mangani tartras" can be tricky to decipher without some knowledge of its origins. It is likely derived from the mineral "manganotantalite," which contains manganese and tantalum. The "tartras" portion is less clear but may refer to "tartaric acid," which can be found in some minerals. Using the International Phonetic Alphabet (IPA), one can spell out the pronunciation as /mæŋɡəni tɑrtrəs/, emphasizing the hard "g" sound and the stress on the second syllable of both words.
Manganese tartrate, occurs as white or light reddish crystals; employed in anemia and chlorosis in doses of gr. 2-5 (0.13-0.3).
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.