Date: 202102
Local time of day: 1201-1800
Location: ZZZ.ARTCC, US
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Climb
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Human factors: Communication Breakdown; Training / Qualification
Second reporter function: Pilot Not Flying; Captain
Anomaly: ATC Issue All Types; Deviation - Altitude Excursion From Assigned Altitude; Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented
Contributing factors: Environment - Non Weather Related; Human Factors; Procedure
Primary problem: Environment - Non Weather Related

Narrative: During Climb we Leveled at 17;000 departure switched us to ZZZ Center on XYZ.AA. Upon check in with ZZZ Center we were given the clearance to climb and maintain flight level 290 and 270 knots.  The Captain who was the pilot Monitor at the time read back those instructions and I set the altitude preset to FL290.  During the climb coming through approximately 220/230 we were given traffic at our 2 to 3 o'clock which wasn't a factor. Then while climbing through FL250 ATC called us asking what our altitude was; he then told us that we were assigned FL190.  He then cleared us to FL300. Flight continued without further issue.As pilots we take responsibility for any deviation of this nature and if there's questions it is our duty to ask and ask again to repeat if needed. I have however; noticed that since we've started flying more frequently since COVID that there are many more miscommunications on the radio than normal.I think we need to recognize that with what's been happening with COVID over the last year we as a group have lost a little proficiency especially with regards to radio calls and procedures. A lot of us have been out on the leaves that includes both pilots and controllers.  The only way I can think of to mitigate this is that we're gonna have to slow it down; make sure that we have it right before we do anything.  Maintain a vigilant watch; both on the aircraft and the radios.


Second narrative: after copilot (pf) leved at 17000'; dfw departure control handed us off to ft worth center (ftwc) on 127.000. upon checking in with 'aa461 level 17000'';  i (ca-pm) heard ftwc say for us to climb to fl290 and maintain 270kts. I read back climb to fl290 and maintain 270kts. with the added narrative of 290 on the 'altitude' and 270 on the 'speed' to avoid any confusion between the two. the cp (pf) set 29000 in the altitude window and we both pointed at it confirming what we both heard. ftwc then additionally called traffic at our 2 o'clock; (do not recall distance and alt.); I replied; negative contact; looking. minutes later at 1917z and Passing through fl250; ftwc asked us to say alt; I replied FL250; climbing FL290. Fort Worth Center said; 'Say again?' and I repeated. Fort Worth Center then said; 'I assigned you FL190 for traffic'.  I replied; 'roger'. Fort Worth Center then told us to climb and maintain FL300 (our final altitude) and contact center on the next frequency. following the read-back; I asked if there was any loss of separation from the previously called traffic. Fort Worth Center; replied; 'No; thank God.' we never received any TCAS alert nor did we ever see any traffic displayed on the nav display (ND).I read back the altitude and speed in two different ways. Maybe state 'FL290'; 'twenty-nine on the altitude'; in the future?


Synopsis: Air carrier First Officer reported an altitude overshoot and cited loss of pilot/ATC communication proficiency due to lack of flying as a contributing factor.