{
 "benchmark": "GPT-Live-1 Interpreter Test",
 "published": "2026-09-15",
 "url": "https://www.livelingo.io/research/gpt-live-1-interpreter-test",
 "license": "https://creativecommons.org/licenses/by/4.0/",
 "methodology": {
  "source_audio": "30 synthesised English sentences from the LiveLingo 2026 comprehension benchmark corpus (audio.zip), concatenated with 0.5 s gaps and repeated 3x",
  "stream_duration_ms": 452041,
  "clips_per_run": 90,
  "source_timing": "word-level timestamps over the source audio",
  "alignment": "monotonic dynamic programming matching each output sentence to the source clip whose published reference translation it overlaps most, with a causality constraint; ja matches on kanji and katakana bigrams",
  "pacing": "real-time against absolute deadlines; sender completed within 39 ms of source duration",
  "metric": "completion lag = last committed token of a clip's translation minus that clip's end in the source",
  "coverage_window_ms": 30000
 },
 "systems": [
  {
   "system": "LiveLingo",
   "model": "livelingo-production",
   "pair": "en-es",
   "input_duration_ms": 452041,
   "output_form": "committed text",
   "clips_total": 90,
   "clips_matched": 90,
   "coverage_within_30s_pct": 100,
   "completion_lag_p50_ms": 938,
   "completion_lag_p90_ms": 1300,
   "per_minute_median_ms": {
    "0": 847,
    "1": 1002,
    "2": 780,
    "3": 836,
    "4": 937,
    "5": 958,
    "6": 946,
    "7": 831
   }
  },
  {
   "system": "LiveLingo",
   "model": "livelingo-production",
   "pair": "en-ja",
   "input_duration_ms": 452041,
   "output_form": "committed text",
   "clips_total": 90,
   "clips_matched": 90,
   "coverage_within_30s_pct": 100,
   "completion_lag_p50_ms": 878,
   "completion_lag_p90_ms": 1376,
   "per_minute_median_ms": {
    "0": 884,
    "1": 857,
    "2": 926,
    "3": 936,
    "4": 820,
    "5": 824,
    "6": 868,
    "7": 836
   }
  },
  {
   "system": "Gemini 3.5 Live Translate",
   "model": "gemini-3.5-live-translate-preview",
   "pair": "en-es",
   "input_duration_ms": 452041,
   "output_form": "speech + transcript",
   "clips_total": 90,
   "clips_matched": 90,
   "coverage_within_30s_pct": 100,
   "completion_lag_p50_ms": 1512,
   "completion_lag_p90_ms": 2099,
   "per_minute_median_ms": {
    "0": 1473,
    "1": 1638,
    "2": 1626,
    "3": 1580,
    "4": 1481,
    "5": 1534,
    "6": 1353,
    "7": 1446
   }
  },
  {
   "system": "Gemini 3.5 Live Translate",
   "model": "gemini-3.5-live-translate-preview",
   "pair": "en-ja",
   "input_duration_ms": 452041,
   "output_form": "speech + transcript",
   "clips_total": 90,
   "clips_matched": 89,
   "coverage_within_30s_pct": 99,
   "completion_lag_p50_ms": 1917,
   "completion_lag_p90_ms": 3341,
   "per_minute_median_ms": {
    "0": 2514,
    "1": 1908,
    "2": 1868,
    "3": 2437,
    "4": 1659,
    "5": 2125,
    "6": 1780,
    "7": 2053
   }
  },
  {
   "system": "gpt-realtime-translate",
   "model": "gpt-realtime-translate",
   "pair": "en-es",
   "input_duration_ms": 452041,
   "output_form": "speech + transcript",
   "clips_total": 90,
   "clips_matched": 89,
   "coverage_within_30s_pct": 99,
   "completion_lag_p50_ms": 2650,
   "completion_lag_p90_ms": 3556,
   "per_minute_median_ms": {
    "0": 3306,
    "1": 2787,
    "2": 2136,
    "3": 2793,
    "4": 2431,
    "5": 1978,
    "6": 2836,
    "7": 2364
   }
  },
  {
   "system": "gpt-realtime-translate",
   "model": "gpt-realtime-translate",
   "pair": "en-ja",
   "input_duration_ms": 452041,
   "output_form": "speech + transcript",
   "clips_total": 90,
   "clips_matched": 88,
   "coverage_within_30s_pct": 98,
   "completion_lag_p50_ms": 3330,
   "completion_lag_p90_ms": 5158,
   "per_minute_median_ms": {
    "0": 4685,
    "1": 2416,
    "2": 2629,
    "3": 4665,
    "4": 2444,
    "5": 3442,
    "6": 2738,
    "7": 4836
   }
  },
  {
   "system": "GPT-Live-1 (prompted interpreter)",
   "model": "gpt-live-1",
   "pair": "en-es",
   "input_duration_ms": 452041,
   "output_form": "speech + transcript",
   "clips_total": 90,
   "clips_matched": 88,
   "coverage_within_30s_pct": 98,
   "completion_lag_p50_ms": 11724,
   "completion_lag_p90_ms": 14157,
   "per_minute_median_ms": {
    "0": 5730,
    "1": 10433,
    "2": 14068,
    "3": 10716,
    "4": 13405,
    "5": 10040,
    "6": 11413,
    "7": 13742
   }
  },
  {
   "system": "GPT-Live-1 (prompted interpreter)",
   "model": "gpt-live-1",
   "pair": "en-ja",
   "input_duration_ms": 452041,
   "output_form": "speech + transcript",
   "clips_total": 90,
   "clips_matched": 70,
   "coverage_within_30s_pct": 17,
   "completion_lag_p50_ms": 51845,
   "completion_lag_p90_ms": 94016,
   "per_minute_median_ms": {
    "0": 10960,
    "1": 31579,
    "2": 44940,
    "3": 60312,
    "4": 80321,
    "5": 95042,
    "6": 97566
   }
  }
 ]
}