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hello grammarians we're talking about vowel shifting in irregular verbs which is gonna sound a little weird but they're with me to review what a vowel is super-quick a vowel is any sound that your mouth can make while your tongue isn't touching your lips or your teeth or the roof of your mouth basically and in English we render vowels in the following way ay-yi I owe you and sometimes y or as it is commonly pronounced that uh that parts not true but here is what's true is that you produce vowels from different parts of your mouth you can produce a vowel in front of your mouth you can produce it in the center of your mouth and you can produce it all the way back in your throat and what does this have to do with irregular verbs I'm so glad you asked let's draw a chart so I'm going to put three things on this chart the present the past and the past perfect which is when you're talking about something in the past that is completed and we form that in English by combining that verb with have so have walked have said have done now in most cases with most regular verbs the past perfect and the past form are the same the same thing but in some very rare cases and that's why we're talking about these they're different and let's begin with the first one in the present tense we say I sing in the past tense we would say she sang and in the past perfect you would say they have sung so it's weird right because the vowel changes this vowel sound it actually bounces along your mouth it goes from front to middle to back as you go further and further back in time which i think is really cool a same thing with the word drink in the present tense it's I drink in the past tense it's I drank and in the past perfect it's I had drunk there are other verbs that follow this formula too like ring ring rang rung for ringing a bell but for the rest of this we're just going to talk about verbs where the past and the past perfect are the same and there's still a vowel shift going on between the present and the so if you take a word like when the present tense is win the past tense is won and the past perfect is also one we had won the game we won the game so that vowel shift goes from it to uh the verb to find so in the present tense it's find and in the past and past perfect it's found it goes from ie to au s-- it becomes Sat sneak becomes snuck and run becomes ran and run is a weird one because the past perfect form of run is run he had run not he had ran and those are some of the front to back sound shifts it at or it or I tau that you will encounter when you're learning irregular verbs in English you can learn anything David out