Yes, it is very possible for leads. Before you can call someone or an organization a lead, you must have received several information from them, which includes name and other essential information. Hence, a personalization can be used to reference a lead's recent conversion in an email campaign if required.
JavaScript currently stands as the most commonly-used language in the world (69.7%), followed by HTML/CSS (62.4%), SQL (56.9%), Python (41.6%) and Java (38.4%).