Speaking is expected of virtually all of us whether we are managers or not. Often that means in formal business English and more often today in other languages as well. Employers will be assessing you on grammar, vocabulary size and use, and how effective you deliver your ideas.
You may think that your job role does not require speaking, perhaps thinking that your field does not require great oration, think again. Even in heavy content science areas like engineering, accounting and computer science, employers look for the employees who can present the ideas, influence clients, and communicate well in a team.
It is likely that speaking will not be the focus of your job, but it will be a factor in promotion and opportunity. If you are in a lab, the person who speaks for your team will be seen as the leader. In a clinical situation, clear instructions will be imperative for patient understanding and healthy behavior.
Attend courses on communication skills, if you are working on an accent perhaps you have a thick local accent, you might benefit from a speech coach. Some employers are looking for very precise speech. Stretch yourself by volunteering to represent your group whatever it might be. Employers will be paying attention to these experiences when you apply. Employers will be listening to see if you adjust your language usage to the situation and audience. Having just the skills of your discipline is never enough.