Summarize:

If you continually get into conflicts with your sibling, you might want to address the problem. Start by stating the obvious. That is, what's bothering you about the situation and why. It's important to address your views and then give your sibling a chance to respond. After your sibling has been talking for awhile, interrupt with something like, "I don't like the way you're talking to me right now" or "I feel like you're dominating this conversation." Try to remain as calm as possible. Getting hostile and trying to yell over someone will only escalate the situation. When communicating a problem, it's important to use "I" statements. These are statements that strive to express things in terms of feelings rather than facts. This can be helpful when confronting your sibling as they will feel you're expressing yourself and your emotions rather than trying to place external judgment on the situation.  I statements begin with "I feel." After stating "I feel" you will describe your emotion and then explain the behavior that leads you to feel this way. Using "I" statements can help with conflict as they can feel less judgmental. You're not making a sweeping judgment about the situation or placing blame on one person. Instead, you're just stating how the situation makes you feel. For example, don't say, "You're inconsiderate when you talk over me and put me down about not finishing my homework." Rephrase this using an "I" statement. Say something like, "I feel upset when you lecture me about my homework because it adds to my stress level." Sometimes, even if you talk as respectfully as possible your sibling will just not stop talking. They may even become hostile, despite your best efforts to resolve the situation. If your sibling keeps talking over you and disrespecting you, it's best to simply end the conversation. Say something like, "I don't think we're getting anywhere and I don't feel comfortable right now." Then, leave the conversation.
Present the problem. Use "I" statements. End the conversation if necessary.