“Spear” is a fine Old English word with many Germanic and Norse cognates.  It is unlikely that Latin sparus is related.

• 14.041 marching with many spearmen
• 15.044 The next morning early a company of spearmen
• 17.036 and spearmen now hidden
• 17.050 a thousand of their spearmen leapt down
• 17.058 came many of the spearmen of the elves.

“spear, n.1.” OED Online. Oxford University Press, June 2015. Web. 29 July 2015.