diff --git a/components/play-button.tsx b/components/play-button.tsx
index 40c7b08..d8621fe 100644
--- a/components/play-button.tsx
+++ b/components/play-button.tsx
@@ -1,9 +1,7 @@
 import { Button } from "@mantine/core";
 import { useHotkeys } from "@mantine/hooks";
-import { useEffect } from "react";
 
 let audioContext: AudioContext;
-// let audioQueue: string[] = [];
 let currentlyPlaying = false;
 
 const playAudioBuffer = (buffer: AudioBuffer): Promise<void> => {
@@ -22,11 +20,11 @@ const playAudioBuffer = (buffer: AudioBuffer): Promise<void> => {
 export const playAudio = (urlOrDataURI: string): Promise<void> => {
   return new Promise((resolve, reject) => {
     if (!urlOrDataURI) {
-      resolve();
+      return resolve();
     }
 
     if (currentlyPlaying) {
-      return;
+      return resolve();
     }
 
     currentlyPlaying = true;
@@ -61,20 +59,13 @@ export const playAudio = (urlOrDataURI: string): Promise<void> => {
 
 /** A React component  */
 export function PlayButton({ dataURI }: { dataURI: string }) {
-  const playSound = () => {
+  const playSound = async () => {
     if (dataURI) {
-      playAudio(dataURI);
+      await playAudio(dataURI);
     }
   };
   useHotkeys([["c", playSound]]);
 
-  // Use the useEffect hook to listen for changes to dataURI
-  useEffect(() => {
-    if (dataURI) {
-      playAudio(dataURI);
-    }
-  }, [dataURI]);  // Dependency array includes dataURI
-
   if (!dataURI) {
     return (
       <>
diff --git a/components/record-button.tsx b/components/record-button.tsx
index f20b1be..622f966 100644
--- a/components/record-button.tsx
+++ b/components/record-button.tsx
@@ -105,6 +105,7 @@ type Props = {
   onStart?: () => void;
   onRecord: (data: string) => void;
   lessonType: string;
+  disabled?: boolean;
 };
 export function RecordButton(props: Props) {
   const { isRecording, stop, start } = useVoiceRecorder(async (data) => {
@@ -114,9 +115,11 @@ export function RecordButton(props: Props) {
     props.onRecord(b64);
   });
   const doStart = () => {
-    props.onStart?.();
-    start();
-  }
+    if (!props.disabled) {
+      props.onStart?.();
+      start();
+    }
+  };
   useHotkeys([
     [
       "v",
@@ -138,11 +141,11 @@ export function RecordButton(props: Props) {
       break;
   }
   return isRecording ? (
-    <Button onClick={stop} color="red" fullWidth>
+    <Button onClick={stop} color="red" fullWidth disabled={props.disabled}>
       [V]⏹️Submit Answer
     </Button>
   ) : (
-    <Button onClick={start} fullWidth>
+    <Button onClick={start} fullWidth disabled={props.disabled}>
       [V]⏺️{buttonText}
     </Button>
   );
diff --git a/pages/_study_reducer.ts b/pages/_study_reducer.ts
index dd8562f..b93528e 100644
--- a/pages/_study_reducer.ts
+++ b/pages/_study_reducer.ts
@@ -12,10 +12,8 @@ export type Quiz = {
 
 type State = {
   numQuizzesAwaitingServerResponse: number;
-  currentQuizIndex: number;
   errors: string[];
-  quizIDsForLesson: string[];
-  failedQuizzes: Set<string>;
+  quizIDsForLesson: number[];
   phrasesById: Record<string, Quiz>;
 };
 
@@ -24,11 +22,10 @@ type LessonType = keyof Quiz["audio"];
 type QuizResult = "error" | "failure" | "success";
 
 type Action =
-  | { type: "WILL_GRADE" }
-  | { type: "ADD_ERROR"; message: string }
-  | { type: "FAIL_QUIZ"; id: string }
-  | { type: "FLAG_QUIZ"; id: string }
-  | { type: "DID_GRADE"; id: string; result: QuizResult };
+  | { type: "WILL_GRADE"; id: number }
+  | { type: "USER_GAVE_UP"; id: number }
+  | { type: "FLAG_QUIZ"; id: number }
+  | { type: "DID_GRADE"; id: number; result: QuizResult };
 
 export type CurrentQuiz = {
   id: number;
@@ -39,29 +36,26 @@ export type CurrentQuiz = {
   repetitions: number;
 };
 
-export function gotoNextQuiz(state: State): State {
-  return {
-    ...state,
-    currentQuizIndex: state.currentQuizIndex + 1
-  };
+export function gotoNextQuiz(state: State, lastQuizID: number): State {
+  const filter = (id: number) => id !== lastQuizID;
+  const quizIDsForLesson = state.quizIDsForLesson.filter(filter);
+  return { ...state, quizIDsForLesson };
 }
 
 export const newQuizState = (state: Partial<State> = {}): State => {
   const phrasesById = state.phrasesById || {};
-  const remainingQuizIDs = Object.keys(phrasesById);
+  const remainingQuizIDs = Object.keys(phrasesById).map((x) => parseInt(x));
   return {
-    currentQuizIndex: 0,
     numQuizzesAwaitingServerResponse: 0,
     phrasesById,
     quizIDsForLesson: remainingQuizIDs,
     errors: [],
-    failedQuizzes: new Set(),
     ...state,
   };
 };
 
 export function currentQuiz(state: State): CurrentQuiz | undefined {
-  const quizID = state.quizIDsForLesson[state.currentQuizIndex];
+  const quizID = state.quizIDsForLesson[0];
   const quiz = state.phrasesById[quizID];
   if (!quiz) {
     return undefined;
@@ -74,7 +68,9 @@ export function currentQuiz(state: State): CurrentQuiz | undefined {
   if (quiz.repetitions < 2) {
     lessonType = "dictation";
   } else {
-    lessonType = Math.random() > 0.5 ? "listening" : "speaking";
+    const nonce = quiz.id + quiz.repetitions;
+    const x = nonce % 2;
+    lessonType = x === 0 ? "listening" : "speaking";
   }
   return (
     quiz && {
@@ -88,67 +84,36 @@ export function currentQuiz(state: State): CurrentQuiz | undefined {
   );
 }
 
-export function quizReducer(state: State, action: Action): State {
+function reduce(state: State, action: Action): State {
   switch (action.type) {
-    case "ADD_ERROR":
-      return { ...state, errors: [...state.errors, action.message] };
-
-    case "FAIL_QUIZ":
-      // Add to failed quiz set.
-      const failedQuizzes = new Set(state.failedQuizzes);
-      failedQuizzes.add(action.id);
-      // Remove from list of remaining quizzes.
-      const remainingQuizIDs = state.quizIDsForLesson.filter(
-        (id) => id !== action.id,
-      );
-      return gotoNextQuiz({
-        ...state,
-        failedQuizzes,
-        quizIDsForLesson: remainingQuizIDs,
-      });
-
+    case "USER_GAVE_UP":
     case "FLAG_QUIZ":
-      const filter = (id: string) => id !== action.id;
-      return gotoNextQuiz({
-        ...state,
-        quizIDsForLesson: state.quizIDsForLesson.filter(filter),
-      });
-
+      return gotoNextQuiz(state, action.id);
     case "WILL_GRADE":
       return {
         ...state,
         numQuizzesAwaitingServerResponse:
           state.numQuizzesAwaitingServerResponse + 1,
       };
-
     case "DID_GRADE":
       let numQuizzesAwaitingServerResponse =
         state.numQuizzesAwaitingServerResponse - 1;
-      const nextState = {
-        ...state,
-        numQuizzesAwaitingServerResponse,
-      };
-      switch (action.result) {
-        case "failure":
-          return gotoNextQuiz({
-            ...nextState,
-            failedQuizzes: new Set(state.failedQuizzes).add(action.id),
-          });
-        case "error":
-          // In the case of a server error,
-          // we push the quiz onto the end of the list
-          // and try again later.
-          return gotoNextQuiz({
-            ...nextState,
-            quizIDsForLesson: [...state.quizIDsForLesson, action.id],
-          });
-        case "success":
-          return gotoNextQuiz({ ...nextState });
-        default:
-          throw new Error("Invalid quiz result " + action.result);
-      }
+      return gotoNextQuiz(
+        {
+          ...state,
+          numQuizzesAwaitingServerResponse,
+        },
+        action.id,
+      );
     default:
       console.warn("Unhandled action", action);
       return state;
   }
 }
+
+export function quizReducer(state: State, action: Action): State {
+  const nextState = reduce(state, action);
+  // Do debugging here:
+  // console.log(action.type);
+  return nextState;
+}
diff --git a/pages/study.tsx b/pages/study.tsx
index a3d87eb..c9ee3e0 100644
--- a/pages/study.tsx
+++ b/pages/study.tsx
@@ -1,8 +1,8 @@
-import { PlayButton } from "@/components/play-button";
+import { PlayButton, playAudio } from "@/components/play-button";
 import { RecordButton } from "@/components/record-button";
 import { trpc } from "@/utils/trpc";
 import { Button, Container, Grid, Header, Paper } from "@mantine/core";
-import { useReducer, useState } from "react";
+import { useEffect, useReducer, useState } from "react";
 import Authed from "./_authed";
 import {
   Quiz,
@@ -24,8 +24,8 @@ type Props = {
 interface CurrentQuizProps {
   quiz: CurrentQuiz;
   inProgress: number;
-  doFail: (id: string) => void;
-  doFlag: (id: string) => void;
+  doFail: (id: number) => void;
+  doFlag: (id: number) => void;
   onRecord: (audio: string) => void;
 }
 
@@ -33,8 +33,8 @@ function CurrentQuiz(props: CurrentQuizProps) {
   const { quiz, onRecord, doFail, doFlag, inProgress } = props;
   const [isRecording, setIsRecording] = useState(false);
   useHotkeys([
-    ["x", () => doFail("" + quiz.id)],
-    ["z", () => doFlag("" + quiz.id)],
+    ["x", () => doFail(quiz.id)],
+    ["z", () => doFlag(quiz.id)],
   ]);
   if (!quiz) {
     let message = "";
@@ -68,6 +68,7 @@ function CurrentQuiz(props: CurrentQuizProps) {
       </Grid.Col>
       <Grid.Col span={4}>
         <RecordButton
+          disabled={!!props.inProgress}
           lessonType={quiz.lessonType}
           onStart={() => {
             setIsRecording(true);
@@ -81,7 +82,7 @@ function CurrentQuiz(props: CurrentQuizProps) {
       <Grid.Col span={4}>
         <Button
           disabled={isRecording}
-          onClick={() => doFail("" + quiz.id)}
+          onClick={() => doFail(quiz.id)}
           fullWidth
         >
           [X]❌Fail Item
@@ -90,7 +91,7 @@ function CurrentQuiz(props: CurrentQuizProps) {
       <Grid.Col span={4}>
         <Button
           disabled={isRecording}
-          onClick={() => doFlag("" + quiz.id)}
+          onClick={() => doFlag(quiz.id)}
           fullWidth
         >
           [Z]🚩Flag Item #{quiz.id}
@@ -132,7 +133,7 @@ function Failure(props: {
 }) {
   const style = {
     background: "salmon",
-    border: "1px dashed pink"
+    border: "1px dashed pink",
   };
   return (
     <div style={style}>
@@ -166,9 +167,13 @@ function Study({ quizzes, totalCards, quizzesDue, newCards }: Props) {
   } | null>(null);
   const needBetterErrorHandler = (error: any) => {
     console.error(error);
-    dispatch({ type: "ADD_ERROR", message: JSON.stringify(error) });
   };
   const quiz = currentQuiz(state);
+  useEffect(() => {
+    if (quiz) {
+      playAudio(quiz.quizAudio);
+    }
+  }, [`${quiz?.id} + ${quiz?.lessonType}`]);
   if (!quiz) {
     location.reload();
     return <div>Session complete.</div>;
@@ -187,10 +192,10 @@ function Study({ quizzes, totalCards, quizzesDue, newCards }: Props) {
       </span>
     );
   })();
+  const { id, lessonType } = quiz;
 
   return (
     <Container size="xs">
-      {state.errors.length ? "ERROR DETECTED!?!?!" : ""}
       <Header
         height={80}
         style={{
@@ -207,14 +212,11 @@ function Study({ quizzes, totalCards, quizzesDue, newCards }: Props) {
       {header}
       <CurrentQuiz
         doFail={(id) => {
-          dispatch({ type: "FAIL_QUIZ", id });
-          failPhrase
-            .mutateAsync({ id: parseInt(id, 10) })
-            .catch(needBetterErrorHandler);
+          dispatch({ type: "USER_GAVE_UP", id });
+          failPhrase.mutateAsync({ id }).catch(needBetterErrorHandler);
         }}
         onRecord={(audio) => {
-          const { id, lessonType } = quiz;
-          dispatch({ type: "WILL_GRADE" });
+          dispatch({ type: "WILL_GRADE", id });
           performExam
             .mutateAsync({ id, audio, lessonType })
             .then((data) => {
@@ -250,18 +252,24 @@ function Study({ quizzes, totalCards, quizzesDue, newCards }: Props) {
                   });
                   break;
               }
-              dispatch({ type: "DID_GRADE", id: "" + id, result: data.result });
+              dispatch({
+                type: "DID_GRADE",
+                id,
+                result: data.result,
+              });
             })
             .catch((error) => {
               needBetterErrorHandler(error);
-              dispatch({ type: "DID_GRADE", id: "" + id, result: "error" });
+              dispatch({
+                type: "DID_GRADE",
+                id,
+                result: "error",
+              });
             });
         }}
         doFlag={(id) => {
           dispatch({ type: "FLAG_QUIZ", id });
-          flagPhrase
-            .mutateAsync({ id: parseInt(id, 10) })
-            .catch(needBetterErrorHandler);
+          flagPhrase.mutateAsync({ id }).catch(needBetterErrorHandler);
         }}
         quiz={quiz}
         inProgress={state.numQuizzesAwaitingServerResponse}
@@ -273,31 +281,21 @@ function Study({ quizzes, totalCards, quizzesDue, newCards }: Props) {
 }
 
 function StudyLoader() {
+  const [isReady, setReady] = useState(false);
+  useEffect(() => {
+    // Request microphone permission
+    navigator.mediaDevices
+      .getUserMedia({ audio: true })
+      .then((_stream) => setReady(true));
+  }, []);
   const { data } = trpc.getNextQuizzes.useQuery({});
+  if (!isReady) {
+    return <div>Requesting microphone permission...</div>;
+  }
   if (data) {
-    const cleanData = (i: (typeof data.quizzes)[number]): Quiz => {
-      if (i) {
-        const { dictation, speaking, listening } = i.audio;
-        if (typeof dictation === "string") {
-          if (typeof speaking === "string") {
-            if (typeof listening === "string") {
-              return {
-                ...i,
-                audio: {
-                  dictation,
-                  speaking,
-                  listening,
-                },
-              };
-            }
-          }
-        }
-      }
-      throw new Error("Impossible");
-    };
     return (
       <Study
-        quizzes={data.quizzes.map(cleanData)}
+        quizzes={data.quizzes as Quiz[]}
         totalCards={data.totalCards}
         quizzesDue={data.quizzesDue}
         newCards={data.newCards}