For both professions, you need to go to school before you can become an engineer or a lawyer. Then you have to take a test (EIT for engineers & Bar Exam for lawyers) before you practice. An engineer after so many years can take the PE Exam and become a professional engineer. Meanwhile he needs to practice under the watchful eye of a PE for a period of years, usually 4. While lawyers do not have such a time requirement most join either a law firm of experienced attorneys, join the state or US attorney office or the public defender's office. Most people would not hire a lawyer of less than 5 years experience.
Plenty of attorneys don't need the verbal skills of a trial attorney. They can do estates and trusts, real estate, tax, personal injury, etc. The reason that most flunk out of law school is the amount of work that is required.
Sorry. That's just not how it works from my experience. I wasn't talking just about the skill you need to think and speak on your feet as you do in trial work, whether it's criminal or civil. It doesn't matter what kind of law you do, it's all about language and using language. Tax law, real estate law, estates and trusts, it's all about the meanings of words, how to use words to create the intended effect, as in a will or trust or contract of any kind, and how to interpret words in statute, case law, you name it.
Have you ever taken the LSAT, the exam for entrance into law school? There's not a fact in there, nothing that you can study for or prepare for in any way. It's just page after page of cases in some mythical jurisdiction X, and then reams of questions about it. If you're not good with language and don't have a logical, precise way of thinking you'll fail. Even if you get in, you can easily fail.
It's not apocryphal that law school professors tell their students to look to the right and left, and at least one of them won't be there next year. Sometimes the attrition rate is even higher. You can spend all the hours of the day and night in the library, as most do, trust me, but it won't help if, as Davef says, you can't read quickly and absorb abstract concepts quickly. The sheer number of pages of case law you have to read each day to prepare for classes is staggering. You also can't just read the cases; you have to be able to analyze them to get the essential logic plus the supporting detail, and, when it's your turn to stand up in class and be grilled, and I mean grilled, by the professor on the case, with him twisting your words and the logic, you have to be able to give a good account of yourself. I've seen twenty six year old men break down and cry under grilling like that. It's not like med school. In law school they treat you like a new recruit at boot camp and can make you wish you were never born. It also doesn't matter how great you are at memorization, because to a great extent it's really not about that. It's about, as they say, "thinking" like a lawyer.
Then there's the Bar exam, one for each state you want to practice in. The attrition rate is very high there too. I know people who have had to take it two or three times. I think Michele Obama took the Illinois Bar three times and never managed to pass it.
Other professions are difficult as well. I know getting higher level degrees in engineering and math is no picnic for some people. With good math and visual skills it's doable. I don't know if, even with lots of practice, I would have been able to do it. It certainly would have been harder for me to do it than it was for my brother, whose skills in those areas are far better than mine.
Everyone has different gifts. You have to find yours and then put in all the hours of practice to completely master it.