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We present chemical abundances of red giant branch (RGB) stars in the dwarfspheroidal (dSph) satellite system of Andromeda (M31), using spectral synthesisof medium resolution (R $\sim 6000$) spectra obtained with the Keck IItelescope and DEIMOS spectrograph via the Spectroscopic and PhotometricLandscape of Andromeda's Stellar Halo (SPLASH) survey. We coadd stars accordingto their similarity in photometric metallicity or effective temperature toobtain a signal-to-noise ratio (S/N) high enough to measure average [Fe/H] and[$\alpha$/Fe] abundances. We validate our method using high S/N spectra of RGBstars in Milky Way globular clusters as well as deep observations for a subsetof the M31 dSphs in our sample. For this set of validation coadds, we comparethe weighted average abundance of the individual stars with the abundancedetermined from the coadd. We present individual and coadded measurements of[Fe/H] and [$\alpha$/Fe] for stars in ten M31 dSphs, including the first[$\alpha$/Fe] measurements for And IX, XIV, XV, and XVIII. These fainter, lessmassive dSphs show declining [$\alpha$/Fe] relative to [Fe/H], implying anextended star formation history. In addition, these dSphs also follow the samemass-metallicity relation found in other Local Group satellites. Theconclusions we infer from coadded spectra agree with those from previousmeasurements in brighter M31 dSphs with individual abundance measurements, aswell as conclusions from photometric studies. These abundances greatly increasethe number of spectroscopic measurements of the chemical composition of M31'sless massive dwarf satellites, which are crucial to understanding their starformation history and interaction with the M31 system.

Elemental abundances in M31: [Fe/H] and [{\alpha}/Fe] in M31 Dwarf Galaxies Using Coadded Spectra