The list below seems long, but when you can use all these words with confidence, your English vocabulary will be fully functional. The only reason I tried using the command was because Monchug declared war on my kingdom despite the fact that we had 89 relation and I married his daughter. It gives the alert that peace was declared but it doesn't actually change anything and the only way to get peace is the old fashioned way.
However, it's essential to learn the right English vocabulary words, so you don't waste your time trying to memorize a huge collection with very little benefit. This quest sees you uncover a conspiracy and declare war on your faction’s enemies, acting as a tutorial as well as a chance for you to engage in a bit of Mount and Blade action with your army. Just FYI the declare peace function didn't work. You can try to use the 'diplomacy fixes' mod to change the time limit for peace and war, so you can basically make the war never stops or just make it last long enough for a change to happen (a city/castle taken by other faction etc. The remaining 10% you'll be able to learn from context, or ask questions about. With 2,500 to 3,000 words, you can understand 90% of everyday English conversations, English newspaper and magazine articles, and English used in the workplace.