This thesis focuses on concord structures found in Western Armenian. I label a structure as concord if two morphemes found in the same clause bear the same feature, yet only result in one semantic interpretation of that feature. The main focus of the thesis is that of negative concord in Western Armenian. Other concord phenomena are also examined: complementizer and additive concord. I draw a parallel between all of these structures, demonstrating that they can be analyzed using the same system of Agreement of the relevant features. A striking similarity between all these concord structures is the optionality of the morphemes involved. Negative morphemes, complementizer heads, and additive markers are optional in Western Armenian. These concord structures bring about some issues regarding head directionality. Western Armenian is a generally head-final language. Certain domains exhibit both head-initial and head-final possible structures. These are found in the complementizers and the adpositions of the language. The complementizer phrases (CPs) which contain more than one morpheme bearing the same feature, are comprised of one head final and one head initial morpheme. Either can be uttered without the other being realized, and both are possible in the same clause as well. Variation, in this case with regards to head direction, is usually studied across multiple languages or across phrase types within a single language; however, WA is a language where variation is seen within the same type of phrase. Western Armenian gives us insights into systems that usually only show one setting in any given language. In analyzing these novel patterns of variability I argue that unique stress and prosodic properties help me unlock these puzzles.