The ordinary Irish foot soldiers, made up partly of "bonnachts", or Irish mercenaries maintained by the various nobles, and partly of free peasantry called out to fight. The bonnachts might sometimes be dressed like the gallowglasses, or else like the rising-out, as the peasants were called; that is, no armour, simply the traditional Irish dress of a linen tunic with very wide sleeves, often dyed yellow with saffron, usually worn over tight trews of a plain color, and sometimes covered with a very short coat of goat’s hair or a large mantle or "shag-rug", patterned, and with a long fringe of "an agreeable mixture of colors".

Bonnachts might have been armed with the sparth-axe, but the usual weapons were javelins or "darts" of which each kern had a handful; even the English admitted that the Irish were extraordinarily skilled with this weapon, but said it was "More Noisesome, especially to the Horse, than deadly".

A few of the kern also used the bow, and a sword or spear and shield might be carried; the shields were oval and convex, of wood or basket-work. Each man would also carry a "skean" or long dagger. They were often clean-shaven but wore flowing moustaches and a mop of shaggy hair or "glib" falling over the forehead (banned by the English as making it difficult to recognize their "thievish countenances").

Their tactics were normally those of skirmishers, especially in difficult country where, often, no other troops could move, but they could also charge fiercely in the right circumstances, clashing their weapons together with a loud cry of "Pharroh!" (Probably really "Faire"—"Watch out!"; anyone who didn’t join in was popularly supposed to be wafted off to a mysterious valley in Kerry and Never Seen Again!). What they couldn’t do was to stand up against cavalry in the open.

(Source: http://www.MyArmoury.com)

"Ulster armies were raised by proclamation made in the churches and places of public assembly throughout the north. Each year recruits were called for to serve for the campaigning season, the rates of pay and other terms of service being announced in formal fashion by the recruiting agents. The bonnaughts were formed in companies of nominal hundreds, just as the English companies were. They marched and attacked to the sound of the drum and bagpipes, and they carried colours.

In 1594 O’Neill and his allies had enrolled and billeted in Ulster some 2,000 bonnaughts. Later this number was doubled and trebled. They were trained to some extent by outsiders, by the Butter Captains, and later by Spanish officers and Irishmen who had served in the Spanish armies in the Low Countries. English amazement at their efficiency grew as the war went on. They were, they said in 1595, better trained than Shane O’Neill’s men had been; a year later they were ‘other enemies, and not those that in times past were wont never to attempt Her Majesty’s forces in the plain field, but in some passes or straits.’; they had been ‘infinitely belabored with training in all parts of Ulster’ for the past three years and were now ‘most ready, well disciplined and good marksmen as France, Flanders, or Spain can show’. ‘In discipline and weapons’, said the English, the Irish soldier was ‘little inferior, in body and courage equal, if not superior, to us.’ The men of military age within O’Neill’s confederacy were, by 1598, ‘all soldiers’; there was no longer a distinction between the aristocratic fighting classes and those who had formerly been prohibited by their low birth from bearing arms. Churls, horseboys and servile orders, as well as those ordinary forming part of the rising out and classed as Ceathernaigh."

"… It was said in 1596 that the Irish, having plenty of muskets, fowling pieces, calivers, swords, helmets, powder and shot, had converted most of their kern into musketeers and their galloglas into pikemen."

(Source: Quoted directly from Irish Battles: A Military History of Ireland by G.A. Hayes-McCoy)