For all his many faults, Edward II was - or at least, was capable of being on occasion - a fluent, articulate and persuasive speaker who could think on his feet, as the following story demonstrates. In June 1320, Edward had to travel to Amiens in France to pay liege homage to his brother-in-law Philip V for his French territories, Gascony and Ponthieu. (Philip had succeeded to the throne on the death of his five-day-old nephew John I 'the Posthumous' in November 1316; Edward managed to put off the dread moment of having to kneel to him for more than three and a half years.) Philip's counsellors insisted that Edward swear an oath of personal fealty to the French king as well, and a clerk of Edward's, an eyewitness, gives this account of what followed:
"And when some of the said prelates and nobles leaned towards our said lord [Edward] and began to instruct him, our said lord now turned towards the said king [Philip] without having been advised," and announced: "You will well remember that the homage which we did at Boulogne [in 1308] was done according to the form of the agreement between our ancestors, and according to the form in which our ancestors performed it, and your father [Philip IV] agreed to this form, and we have his letters regarding this, and we have now done homage in this same form. One cannot properly demand another form of us, and we will not recognise the validity of doing it. And as for this fealty, we are certain that we will not do it, and nor should it be demanded of us at a later time, and we are unable to believe that this fealty should be given as you demand of us." The clerk/eyewitness continues "And then the king of France turned to the men of his council, and none of them could say anything to contradict the response of our said lord." [My translation from the French.] 
Edward's fluent response, spoken spontaneously without the benefit of any advice, reduced the French delegation to stunned silence, and the issue of personal fealty was quietly dropped. And thus we can see that whatever else Edward II might have been, he wasn't "a scatter-brained wastrel," "brutal and brainless," "a greater ninny never sat on the English throne" or "a fool" as he has sometimes been described by people (J. Mackinnon, K. H. Vickers, T. F. Tout and May McKisack) who really should know better. (Richard Baker in his Chronicle of the Kings of England says that Edward was "worthy never to have been born." How dare anyone say such a vile thing about another human being? Edward II was deeply flawed, of course, he made numerous mistakes, of course, but he wasn't evil, a sadistic serial killer, a child rapist, a concentration camp guard, a professional torturer, an insane genocidist; whatever did he do to deserve such an incredibly harsh judgement?)
Another speech Edward gave, to parliament in October 1324, still survives (the only one of his speeches to parliament which does), which he delivered in French, his native language. At the time, England and France were at war over Gascony, the War of Saint-Sardos. I won't quote the king's speech in full here as it's pretty long and frankly not terribly interesting, but it begins:
"Lords, I have shown you certain things which concern the crown which have come under debate, as one who is your chief and who has the sovereign keeping of it, and as one who is ready to maintain the crown in all its rights, with your counsel and aid, and to defend it as far as a man can, by the power of all your might, on which matter I have always asked for your counsel, and have done nothing in the said business [i.e. war with France] without counsel, in which I believe that I have done my part."
(Seignurs, joe vous ai monstre ascunes choses qe appendent a la coroune qe cheent en debat, come celi qest vostre chief et qe en ad la sovereyne garde et come celi qest prest est a meintenir la coroune en touz ses dreitz, par conseil et eide de vous, et adeffendre le come un homme purra fere par la puissaunce de tutes voz forces, sur quele chose j'ai touz jours voz conseals demandez et rien en la dite busoigne sanz conseil n'ay fet, par qoi je entenqe avoir fait ce que a moy apartient)
Edward's speech ends "I do not want any concealment or sly evasion between us on such an important matter but to be answered orally, clearly and distinctly, just as the matters are distinctly and openly shown to you." 
A month or so after Edward gave this speech, the envoys of Robert Bruce, king of Scots, arrived in England to say that Robert wanted "to turn the truce into a perpetual peace," that is, the thirteen-year truce which the two men had agreed in 1323. Edward, fighting a war with France, "wrote back that he would willingly consent," but changed his mind when he heard the Scottish demands "that Scotland should be forever free from every English exaction," that Robert should be restored to "a certain barony in Essex" which he had forfeited to Edward I, that the Stone of Scone be restored to Scotland (it remained in England until 1996) and that Edward's son Edward of Windsor marry Robert's daughter to seal the peace. Edward II's reply to all this is a fascinating - and doubtless infuriating, if you're Scottish - illustration of how he had been raised to think of Scotland as part of his own inheritance. This is given by the Vita Edwardi Secundi in Latin, though Edward presumably spoke French; how closely it matches what he really said is a matter for conjecture:
"The Scots have come to us not to draw us into a peace but to seek opportunities for further discord and for unprovoked breaches of the truce. To grant these demands would be much to our loss, and they will return to their own country without satisfaction. For how without prejudice to our Crown can we surrender the right we have in Scotland, which from the coming of the Britons to the coming of the Saxons and down to our own time, is known always to have been subject to our ancestors; which, although in rebellion it often spurned our authority, was, nevertheless, as no one doubts, reduced to its due state of servitude, though unwillingly?...Robert Bruce claims the inheritance which my father once took from him for manifest crime, and it is not fitting that the son should make void what the father decreed. For we know that my father, when Scotland had been conquered, took with him the famous royal stone [of Scone] as a sign of victory; and if we were to restore it we should seem basely to repudiate the right thus acquired. Nevertheless, we should make little difficulty about returning the stone, if their other demands were not beyond all reason...But, as their demands are too damaging to us, they shall return home unsatisfied." 
Finally, here's a speech of Edward II also cited in the Vita, dating from early 1322, when Edward was on campaign against the Contrariants and Andrew Harclay, sheriff of Cumberland, came to ask him for aid to defend the north against Robert Bruce's friends and allies James Douglas and Thomas Randolph, who had invaded England with their armies as soon as the two-year truce between England and Scotland expired at Christmas 1321. Edward's attitude towards his domestic enemies and the Scottish invasions could hardly be clearer:
"You may know for certain, Andrew, that if Robert Bruce attacks me from behind, and my own men, who have committed such enormities against me, should appear in front, I would attack the traitors and leave Robert Bruce alone. Small wonder if the Scots, who are in no way bound to me, invade my kingdom, while those who are bound to me by fealty and homage rise against me, plunder my men and set fire to my towns; if the servants attack the lord, how much more will a foreigner?...Return to your own country, and keep the strongholds committed to you; I shall pursue my traitors whithersoever they betake themselves, and I shall not turn back until they are brought to naught." 
Given that Edward was shortly to execute at least twenty men for treason and numerous other crimes and imprison dozens more, he was as good as his word, as perhaps Hamo Hethe, bishop of Rochester, had guessed that he would be. The day after the Contrariants forced Edward to consent to the Despensers' exile in August 1321, Edward ate breakfast at Westminster with Hethe, who told him consolingly that he would soon "amend the defeat." Edward responded that he "would within half a year make such an amend that the whole world would hear of it and tremble." 
1) E. Pole Stuart, 'The Interview between Philip V and Edward II at Amiens in 1320', English Historical Review, 41 (1926), pp. 412-415.
2) The Parliament Rolls of Medieval England, ed. C. Given-Wilson et al, October 1324 parliament.
3) Vita Edwardi Secundi, ed. N. Denholm-Young, pp. 131-134.
4) Ibid., pp. 120-121.
5) Parliament Rolls of Medieval England, July 1321 parliament, citing Historia Roffensis.