シャドーイング練習: He Realized his Mistake - 動画で英語スピーキングを学ぶ

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Of all the legendary computer scientists, Tony Hoare stands distinct among them all.

Let's just put it this way.

70 % of all enterprise

Java errors that have been logged can be attributed to a single decision he made in 1965.

In fact, one of the largest Google outages in recent memory was caused by a null pointer exception.

We're talking about a basic if statement was skipped and seven hours of downtime was experienced with three hours globally affecting many, many services, including Spotify.

Costing many millions in damages, and all of this could be traced back to that one 1965 decision.

But it's not all epically bad decisions from Sir Tony Hoare.

He's also created some of the fastest and most memory -efficient sorting and statistical algorithms.

And his professional and academic work have laid the foundations for languages like Pascal and Go.

I know, some of you think

Go's a blunder, but he made the good parts.

And throughout his career, he has been honored slash awarded more than 21 times,

including the Turing Award, some consider the highest award in all of computer science, and he was knighted for his contribution to education and computer science.

But today, he receives the most prestigious honor of them all.

Programmer of the month at the startup.

Being knighted, programmer of the month.

But before we remember

Tony's greatest disasters and achievements, a quick thank you from the sponsors.

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Sir Charles Anthony Richard Hoare was born January 11, 1934 in what is now known as Sri Lanka.

He was educated in England at the finest of schools.

We are talking, of course, about the Dragon School in Oxford and the King School in Canterbury.

they serve tea

and fine fine table cookies i don't

i don't even know what they do with those type of places

it sounds very fancy okay i went to montana state university okay

i'm not allowed to have these type of experiences later on he entered merton college in oxford in 1952

and after graduating he spent 18 months studying russian of course

he had to do this as part of his compulsory duty to the royal navy

now this is where it actually gets pretty interesting because during his time in Russia at Moscow State University.

Also looks like he went to MSU like I did.

Go Bobcats for here!

Before I show you Quicksort, I did want to just say that

Tony Hoare raw dogs this on a pen and piece of paper in the middle of Russia.

Okay, there was no computer.

There wasn't even a programming language with recursion at the time of him inventing this.

It's like he has chat GPT in his head.

He can just close his eyes and imagine problems and get answers out of it.

Quicksort's actually rather easy to understand.

You pick an element, any random element.

I just picked the middle element.

And then you put everything that is smaller on one side and everything that is larger on the other side.

After that, 14 is now sorted.

Everything on the left -hand side is smaller.

Everything on the right -hand side is larger.

So if we do it again, we just consider the smaller side.

Again, we just pick the middle element.

We sort, and there you go.

7 and 3 are now sorted.

We do it again, pick the middle element, put everything smaller on the right, everything larger on the left, 11 is now sorted.

And since there's only one on the left, 13 is now sorted.

Do the same thing again.

They're both sorted.

Jump over to the other side.

Go in the middle.

Everything smaller goes on one side.

Everything larger on the other side.

Bada bing, bada boom.

That is quick sort.

Okay, so you're probably thinking, what's the big deal?

It's just sorting.

It's not even that awesome.

Well, actually, first off, it was very, very awesome.

I want to put a little couple things in perspective.

First off, runtime.

It has n log n for runtime, meaning that its growth, as the array gets bigger, will become proportional to N log N.

So that's actually pretty dang good.

Second, it does not require a lot of memory.

Now, this is very, very important because back in the day, back in the old days in 1960, one kilobyte of RAM, magnetic core RAM,

was $5 ,000 in the old US dollars, which means in today's dollars, that's like $50 ,000 per kilobyte.

Who would kill a byte for $50 ,000?

So as you can see, this is extremely important.

Now, he never actually got the chance to implement this.

This was just a pure thought exercise for a long, long time.

Until one day when he joined the Elliott Brothers in 1960 and his very first task was to implement Shellsort.

Now, of course, him being the confident fella he is, he went to his boss, which he has named Pat.

And he went, hey, yo, boss, uh, shell sword sucks.

I could make it much, much better.

And his boss was like, there ain't no way you're gonna make it any better.

And they actually ended up betting six pence.

I don't know what six pence is.

That sounds like something out of a nursery rhyme.

I don't know what's going on over in the UK or whatever they're doing over there.

But nonetheless, they bet a few dollars on the line or many dollars, or I don't know how many dollars that is.

What is it in freedom units?

I don't know.

Anyway, so they bet.

100

And then whore ends up getting on the whiteboard and starts drawing out some boxes and arrows and explains his algorithm.

101

His boss, Pat, implements the algorithm, admits he is wrong, and later

102

Tony Hoare does say that he was given six pence for winning the argument.

103

During his time at Elliott Brothers, he also convinced them to implement Algo 60 as opposed to their own bespoke proprietary language.

104

This proved to be a large commercial success, and Tony was showered with accolades.

105

Obviously, implementing Algo 60, he got really excited about it, and a few years later,

106

he started working on a language with Nicholas Wirth called Algo W, a successor to Algo 60.

107

Now, it's his work on Algo W that became so quintessential to all of our lives.

108

The emotional damage you have experienced can be traced back to these decisions right here.

109

Let me read you the abstract from his QCon talk in 2009.

110

I call it my billion -dollar mistake.

111

It was the invention of the null reference in 1965.

112

At the time, I was designing the first comprehensive type system for references in an object -oriented language, ALGOL W.

113

My goal was to ensure that all use of references should be absolutely safe.

114

Hilarious, okay?

115

I mean, we're talking about null references here, people.

116

I just, my heart is warm to be like, we're going to make it absolutely safe.

117

No references.

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With checking performed automagically by the compiler, but I couldn't resist the temptation to put in a Null reference.

119

I mean, this guy is having like a Lord of the Rings level style temptation.

120

He just couldn't.

121

The ring was too powerful.

122

Null references is, in fact, the power of Sauron.

123

Simply because it was so easy to implement.

124

This had led to innumerable errors, vulnerabilities, and system crashes, which have probably caused a billion dollars of pain and damage in the last 40 years.

125

The real question is, how costly was the Null Pointer decision?

126

Well, first off, as a student at MSU Go Bobcats, I will tell you that I spent many a day trying to debug damn null references.

127

Okay, so emotionally, it was like a billion dollars just for me.

128

But I think

129

that you can recall a time just a couple years ago

130

where the world's largest outage could be traced back to a null reference.

131

One of the most famous ones was from June 12, 2025 from Google Cloud.

132

Effectively, all it was was they just didn't check for a null pointer.

133

And of course, null pointer happened.

134

API and auth went down and then globally everything just did not work.

135

And of course this went on for about seven and a half hours until the fix was fully rolled out.

136

There's just something that tickles me that I find so funny about this entire situation in which

137

Tony Hoare over here, he just wanted to be able to create a type safe language

138

that was absolutely safe with all references and ends up creating the greatest debacle that we're still recovering from to this day.

139

The reality probably is that

140

if he did not invent it somebody else would have just like the AI race really

141

it's just like the exact same thing

142

but at the end of the day it is attributed to him

143

and his algo w work

144

now one of his largest contributions to the field of computer science would be communicating sequential processes

145

now I'm just going to demonstrate a quick example of what this means in practice by showing

146

you a little bit of code

147

and go now I know a lot of you are rust boys out there

148

and you're probably a little upset

149

that I'm using go just just just walk with me because it's the simplest all right so we have two processes here.

150

We have this outer process, which creates a channel, waits on the channel, and then prints out the message it gets from a channel.

151

We have a second process that's going to do some work

152

and then ultimately hand that work out in which I'm calling Hello World.

153

So that means we create the channel in process one.

154

Process two is going to just start executing.

155

Process one now is just going to be waiting.

156

It's going to be waiting synchronously until process two communicates.

157

This is a very important part of communicating sequential processes.

158

Then finally, when the work is done in process two and we can now communicate,

159

now process one receives the message and is able to move forward.

160

So one of the core ideas of CSP is that communication is a synchronous handshake.

161

And as you can see right there, process one had to wait until process two communicated.

162

So both process two and one have to wait for each other because the communication is synchronous.

163

Now, obviously, you can get around this by creating buffers.

164

That way process two can theoretically send more messages.

165

But the simple idea is that all processes have to communicate in a synchronous handshake.

166

That processes are units of behavior and do not share variables.

167

Now, I know in that

168

Go example, I did do a little bit of sharing, but we can just ignore it for now.

169

Again, I'm just explaining this in the most simple and obvious practical terms, not really in the calculus side of things.

170

You can go look up the calculus

171

and how events are supposed to be instantaneous

172

and how.. receivers are supposed to have an alphabet in which they are the type of events that they receive.

173

If you've ever done any elixir, this probably sounds pretty dang familiar to the actor pattern because, well, I mean, it is.

174

So at the end of the day, Tony Hoare's contributions to computer science have been actually quite a bit more than I even threw out there.

175

I didn't even talk about Quick Select and some of his statistical algorithms

176

that he helped accomplish his practical work on the Algol compiler.

177

Much like his predecessor, Edgar Dykstra, who also was a recipient of the Programmer of the Month Award,

178

he has a few banger quotes that I'd like to read for you.

179

When he thought and talked about ALGOL 60, he said the following,

180

Here's a language so far ahead of its time that it was not only an improvement on its predecessor,

181

but also nearly on all of its successors.

182

The man had a way with words.

183

There are two ways of constructing software design.

184

One way is to make it so simple that there are obviously no deficiencies,

185

and the other way is to make it so complicated that there are no obvious deficiencies.

186

The first method is far more difficult.

187

Oh my gosh, the man can see around corners if he, he was, he technically did die this year in March,

188

but I'm sure he saw some of what the AI was doing, and I wonder what he thought about this right here,

189

and just the massive amounts of code we have produced.

190

Later in Tony Hoare's career, he received the second most honorable distinction, being knighted by Queen Elizabeth II, which is why we actually call him

191

Sir Tony Hoare.

192

Of course, if you didn't know, Program of the Month being the most important designation one can possibly get.

193

Now, I did not get to all of Tony Hoare's amazing accomplishments and the things that he had done.

194

I didn't even talk about Quick Select.

195

I didn't even talk about all the cool work he really did on Algo W

196

or about his unifying theory of programming or the philosopher's dining, which, by the way, the dining philosopher's problem, Pretty gross that they're sharing silverware, okay?

197

I didn't even want to talk about it because it's unsanitary.

198

But at the end of the day, Tony Hoare's influence will be felt for a very, very, very long time.

199

And it's quite obvious he deserves

200

Programmer of the Month.

201

So here's to you, Sir Tony Hoare, Programmer of the Month.

202

The name is the Primogen.

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このレッスンの語彙とスピーキングのポイント

このスピーキングレッスンは、動画「He Realized his Mistake」を教材にしています。繰り返し出てくる語は次のとおりです：Tony, process, null, reference。この動画には、シャドーイング用の文が202文、単語が2382語あります。音声の長さは12:14です。話す速さは速く、1分あたり約195語です。音のつながりや弱く発音される音が多くなります。英語の頻出3,000語に含まれる単語は81%だけなので、語彙は難しめです。

この動画の重要語彙

動画に出てくる覚えておきたい単語15語を、発音と意味つきで紹介します。

単語	発音	意味
algorithm 名詞	/ˈælɡəɹɪðm̩/	アルゴリズム, 演算手順
null 名詞	/nʌl/	無, 無価値
communicate 動詞	/kəˈmjuːnɪkeɪt/	伝える
implement 動詞	/ˈɪmpləmənt/	実行する, 実現する
element 名詞	/ˈɛləmənt/	要素, エレメント
programmer 名詞	/ˈpɹoʊɡɹæmɚ/	プログラマー
pointer 名詞	/ˈpɔɪn.təɹ/	指し棒
contribution 名詞	/ˌkɑntɹɪˈbjuʃən/	貢献
knight 名詞	/ˈnaɪ̯t/	騎士, ナイト
trace 名詞	/tɹeɪs/	跡, 痕跡
penny 名詞	/ˈpɛni/	ペニー
practical 形容詞	/ˈpɹæk.tɪ.kəl/	実践的な
successor 名詞	/səkˈsɛsɚ/	後任, 後継者
predecessor 名詞	/ˈpɹɛd.ə.sɛs.ɚ/	前任者
attribute 名詞	/ˈæt.ɹɪˌbjut/	性質

動画に出てくる句動詞

単語	発音	意味
go down 動詞		降りる, 降下する
look up 動詞	/ˌlʊk ˈʌp/	見上げる
throw out 動詞	/ˈθɹəʊ ˌaʊt/	捨てる

繰り返し練習したい文

動画に出てくる短く完結した文です。日常会話でそのまま使えます。

Let's just put it this way.
Okay, so you're probably thinking, what's the big deal?
I don't know what six pence is.
I mean, we're talking about null references here, people.

この動画の文法

話し手がよく使っている文型を、動画の実際の表現とともに紹介します。

文型	動画での表現
受動態 be + 過去分詞 — 誰がするかより、何が起きるかに焦点を当てる	have been logged · was caused · was skipped
現在完了形 have/has + 過去分詞 — 過去の出来事が今も関係している	have been logged · have laid · has been honored
関係詞節 who / which + 節 — 人や物について情報を加える	dollars, which means · crashes, which have

注意したい発音

話し手はdidn't, don't, I'mなど、短縮形や弱形を35回使っています。聞こえたとおりの短い形で発音しましょう。

「th」の音: algorithm /ˈælɡəɹɪðm̩/, nonetheless /ˌnʌnðəˈlɛs/, authorization /ˌɔːθəɹaɪˈzeɪʃən/
「sh」と「zh」の音: contribution /ˌkɑntɹɪˈbjuʃən/, temptation /ˌtɛmpˈteɪʃən/, deficiency /dɪˈfɪʃənsi/, efficient /ɪˈfɪʃənt/, shell /ʃɛl/
長い単語（アクセントの位置に注意）: communicate /kəˈmjuːnɪkeɪt/, contribution /ˌkɑntɹɪˈbjuʃən/, statistical /stəˈtɪs.tɪ.kəl/, predecessor /ˈpɹɛd.ə.sɛs.ɚ/, deficiency /dɪˈfɪʃənsi/

日本語話者が苦手な音：

/r/ と /l/ の区別 — /l/ は舌先を歯茎につけ、/r/ はどこにもつけない: algorithm /ˈælɡəɹɪðm̩/, practical /ˈpɹæk.tɪ.kəl/, recall /ɹɪˈkɔl/, hilarious /hɪˈlɛə.ɹi.əs/, legendary /ˈlɛd͡ʒ.ənˌdɛɹ.i/
/v/ — /b/ にならないように、上の歯を下唇に当てる: invent /ɪnˈvɛnt/, server /ˈsɝvɚ/, achievement /əˈt͡ʃiːv.mənt/, comprehensive /ˌkɑm.pɹəˈhɛn.sɪv/, recover /ɹɪˈkʌvɚ/
/f/ — 「フ」ではなく、上の歯と下唇で出す: deficiency /dɪˈfɪʃənsi/, infrastructure /ˈɪnfɹəˌstɹʌkt͡ʃə/, efficient /ɪˈfɪʃənt/, fancy /ˈfæn.si/, buffer /ˈbʌfəɹ/

この動画での練習方法

まず声を出さずに動画を最後まで聞き、知らない単語をメモします。
まず0.75倍速で一文ずつシャドーイングし、慣れてきたら通常の速度に戻します。
自分の声を録音して元の音声と比べます。algorithm, null, communicateなどの単語に特に注意しましょう。

シャドーイングとは？英語上達に効果的な理由

シャドーイング（Shadowing）は、もともとプロの通訳者養成プログラムで開発された言語学習法で、多言語習得者として知られるDr. Alexander Arguelles によって広く普及されました。方法はシンプルですが非常に効果的：ネイティブスピーカーの英語を聞きながら、1〜2秒の遅延で声に出してすぐに繰り返す——まるで「影（shadow）」のように話者を追いかけます。文法ドリルや受動的なリスニングと異なり、シャドーイングは脳と口の筋肉が同時にリアルタイムで英語を処理・再現することを強制します。研究により、発音精度、抑揚、リズム、連音、リスニング力、そして会話の流暢さが大幅に向上することが確認されています。IELTSスピーキング対策や自然な英語コミュニケーションを目指す方に特におすすめです。

シャドーイングのやり方: ステップ別の完全ガイドを読む →

シャドーイング練習: He Realized his Mistake - 動画で英語スピーキングを学ぶ

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