The 4 Most Important Words in Leadership Development Two words are "no-nos"; the other two are positive game-changers.

If you're an entrepreneur used to working on your own, you may not give much thought to your words' impact on people. But if your entrepreneurship has turned into a full-fledged business with employees, managers and coffee makers, you may have to rethink your stance.

Words matter. Using just a single ill-advised word here or an off-putting word there can make the difference between a pleasant, productive discussion and a negative exchange that can have lasting repercussions.

This is particularly true in business leadership situations, where a single word can make or break an interaction between a leader and an employee or team member. Words matter so much because they can determine whether or not your leadership is effective. At a minimum, the wrong word can decrease your degree of leadership effectiveness when you're working so diligently to optimize it.

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The truth is that effective leadership is all about achieving results through relationships. Senior leaders are in a position to have to get the bulk of work done through others. Otherwise, they have no time to work on vision and strategic objectives — i.e., looking out on the horizon for what is needed longer-term to attain the long-term vision. With this in mind, words become the master sail, guiding conversations to take the best path to performance.

Evaluating the impact of every word that can be used in a leader and employee interaction is a bit of a Herculean undertaking. With that said, four specific words merit the most significant level of attention and examination based on their ability to derail a business discussion or elevate it.

In my opinion, two of the words should be on the "no-fly" list; that is, they should never be used in any conversation between leader and employee or even between leaders. They will invariably produce the opposite effect that was intended. Unfortunately, many leaders still employ them regularly, without truly understanding the potential harm they can cause.

The other two words are "antidotes" to the first two entries. When used as substitutes for the two harmful words, they can change the entire direction of a discussion while generating the positive impact that the conversation was intended to have.

The culprits: "Why" and "But."

The saviors: "What" and "And."

With such an impressive build-up, you may be disappointed at how unassuming and innocuous the four words seem. But I can assure you, their power to inspire achievement or quell enthusiasm is not to be understated.

Related: Inspiring Leaders Know to Choose Their Words Carefully

The first entry, "why," is a terrible word to use when you are involved in performance management — even if you want to understand the reason your team member executed a task a certain way or are curious about the reason one of your C-suite peers followed a specific course of action. It doesn't matter how neutrally or benignly you use the word; you can use the best tone possible and put bouquets of flowers around it. Once it enters our head, the term "why" immediately puts us on the defensive. Our brain interprets it as a form of judgment. It causes us to think, "I've done something wrong; now I need to defend or explain myself."

(By the way, if you want to see precisely how the word "why" creates such a defensive posture, try it on your spouse or partner. As you already know, it creates a high degree of defensiveness. The reaction is visceral; we have a better chance of stopping a moving freight train than preventing this reaction.)

So, how do we short-circuit the adverse reaction generated by the word "why"? We simply bring in our four-letter superhero, "what." Substitute the word "what" for "why," and the entire dynamic of the discussion changes. Immediately, when "what" enters the picture, it asks, in an objective, unassuming manner, to recount your activity or action; there is no judgment and, consequently, no defensiveness. You're just asking for information with no agenda. It conveys the message that you are simply trying to understand. Examples are:

• What caused you to do (the task or action)?
• What was the reasoning for (the task or action)?
• What was the thought process behind (the task or action)?

The word "but" may be even worse than "why." "But" is like "why" on steroids. "But" has the power to negate any statement uttered just before it, regardless of how positive it was.

For example, let's say you tell a team member, "Karen, you did a fabulous job on that project, but I would have liked to see it a little earlier." The "but" changes the entire tone and tenor of the statement. What started as a compliment quickly morphed into a perceived denigration of the person's performance – regardless of how minor the infraction was.

Think about it: in the example with Karen, you're trying to acknowledge something that was done well, then piggyback on that positive statement with something you'd like to see done the next time — taking a task performed effectively and offering a way to enhance that performance further. However, there is no piggyback with "but." It has the opposite effect; it wipes out the first part of the statement.

Simply put, the word "but" has no upside.

You've likely already figured it out: the word "and" provides an excellent way to avoid the "but" dilemma. So now you might say, "Karen, I love what you did with that project, and the next time, I'd like to see it earlier." It allows the first phrase to land and the person to actually hear it. It's also a neurolinguistic cue that you want the person to take this next step, and here's precisely the next step.

If you want to make this approach even more successful, use "and" in another way: "Karen, you did a fabulous job on that project. And what do you think of executing it earlier next time?" Now, you've asked a question – a question about what the person thinks. So, while the first use of the word "and" is acceptable, the second is an attempt to gain "buy-in" from the team member.

As a bonus, you've also allowed your employee to let you know if an earlier delivery time is possible. In the first instance, few team members will say no; they'll say, "Sure, I'll do that." The second example allows a team member to say yes while providing an opportunity to voice any concerns about potential issues with fulfilling the request — which can then be followed by asking the team member for suggestions on how the earlier project delivery can be achieved.

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The obvious question is, how difficult is it to excise "why" and "but" from your vocabulary — two words you've likely used for quite some time — and replace them with more empowerment-centric alternatives? If you follow a systematic, three-step approach and work on it daily, you can change the pattern more quickly than you might think.

The three steps to the approach are:

1. Become aware of the pattern: You mentally note it every time you say one of the two words. You can tell yourself, "I'm using the word, and I'm now aware of it."
2. Interrupt it: When you realize that you are running this pattern, you must interrupt it the second you begin. You must catch yourself as early as possible and put the brakes on. You might even tell team members to look for the pattern — they will likely be glad you asked them to assist in your self-improvement.
3. Run the new pattern: You say "what" instead of "why." You say "and" instead of "but." Every time you do that, it starts forming a new neural pathway that will become ingrained relatively quickly.

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There are reams of data demonstrating that it takes about 66 days to change a habit and much less time to change a behavioral pattern. This is because habits live in our conscious mind; behavioral patterns are formed and live in our unconscious mind, the latter processing infinitely more volume and speed than the former. It's a minor change that will make a big difference in your leadership effectiveness and will happen faster than you would imagine.

Words matter for many reasons, not the least of which is how they land in our brains from a neurolinguistic perspective. Certain words we use in a business leadership role can either get team members on board with the corporate journey or have them looking for a different journey. To potentially make such an enormous impact with such few words – that's a journey worth taking yourself.