No, credit cards are generally not accepted by taxis in Buenos Aires city. When arriving at EZE airport, it is advisable to use the reliable Taxi Ezeiza service, which has a booth in the arrivals hall. At this booth, you must prepay a fixed rate, and these taxis do accept credit cards.
Alternatively, another safe and dependable choice at the airport is to opt for "remises" companies such as Tienda León or World Car. These services involve cars with drivers and operate on a flat-rate basis depending on the destination, without metered fares.
While there might be exceptions, as a general rule, taxi drivers in the area may not be fluent in English.