Languages are not my direct field of study, but I am regularly facing decisions that involve a choice of a language or another. The linguistic diversity was part of my everyday life as a child and reached complex levels of development later in the day, once faced with life and professional contexts.
My area of expertise has to do with Central and Eastern Europe and for my PhD I had to refresh and improve my knowledge of Hungarian, a language that I used to speak as a child, but that was relatively neglected once I left the linguistic realm where this language was spoken. Although I had the chance to do interviews and field work in another language than the Hungarian, being able to go directly to the sources and being familiar with a certain mindset helped me tremendously to grasp the chore ideas for my research.
For various professional reasons, once I was extremely interested in a specific geographical area, I realize how important it is to have direct access to sources of the everyday life, such as media but also to be able to communicate with people directly in their mother tongue.
Time is limited and life priorities might be completely other than to spend your time learning a new language every couple of months or so. However, if you want to succeed in your professional assignments, linguistic knowledge is key.
Once upon a time I had for a short time the experience of the diplomatic service. Unfortunatelly, not all of the diplomats I met were able to set a conversation in the language of the country they were assigned to. Those were the worse and the most inefficient parts of the diplomatic corps. Except the information exchanged over a plate with canapés they were unable to understand too much from the complexity of the countries they were working to. They depended on mediated information, on translators and most of their time was spent in offices, reading second hand information.
For the academic research, such a lack of linguistic knowledge creates serious credibility gaps. Big academic centers such as Georgetown University for instance, require as part of the academic preparadness spending a significant amount of time learning a new language, or even more. As many as you need in order to properly understand your topics.
True is also that the complex academic and political life require permanent adaptations and switches of topics. During the Cold War, the knowledge of Russian was mandatory for most of the political scientists and diplomats dipatched on the red part of the Iron Curtain. The Balkan Wars and the Balkans in general turned into the mainstream topic of actuality, therefore many of the academics were faced with the challenge of learning the local languages in the area. Since 11/9, learning Arabic in order to understand the Middle East is mandatory, as most of the funding is generally directed for researches pertaining to this area. Chinese or Persian are also top linguistic priorities.
During an active academic lifetime, an academic might need nowadays to change more than once his or her area of study. However, if he or she wants really to be considered a reliable academic, taking such a challenge is very important. The capacity of having a direct access to sources, both human and of academic and scientific nature, is a guarantee of credibility. Learning a new language nowadays is so easy, by using various online tools and apps. You can do it at the convenience of your home and with minimal investment. But, if you really want to be considered yourself an expert, you have to do it. It is a guarantee of credibility and respect towards your domain and the people that although they have lesser visibility, might have a much better graps of the reality because they speak the language.
A language means more than the knowlege of a couple of words or grammar structure, but it confers direct access to a mindset and a way of thinking. No translation could provide this.