Shadowing Practice: Natural Language Processing - Tokenization (NLP Zero to Hero - Part 1) - Learn English Speaking with Video

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Hi, and welcome to this series on Zero2Hero for Natural Language Processing using TensorFlow.
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If you're not an expert on AI or ML, don't worry.
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We're taking the concepts of NLP and teaching them from first principles.
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In this first lesson, we'll talk about how to represent words in a way that a computer can process them, with a view to later training a neural network that can understand their meaning.
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This process is called tokenization.
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So let's take a look.
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Consider the word listen, as you can see here.
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It's made up of a sequence of letters.
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These letters can be represented by numbers using an encoding scheme.
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A popular one called ASCII has these letters represented by these numbers.
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This bunch of numbers can then represent the word listen.
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But the word silent has the same letters, and thus the same numbers, just in a different order.
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So it makes it hard for us to understand sentiment of a word just by the letters in it.
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So it might be easier, instead of encoding letters, to encode words.
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Consider the sentence, I love my dog.
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So what would happen if we start encoding the words in this sentence instead of the letters in each words?
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So for example, the word I could be one.
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And then the sentence, I love my dog, could be one, two, three, four.
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Now, if I take another sentence, for example, I love my cat, how would we encode it?
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Now we see I love my has already been given one, two, three.
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So all I need to do is encode a cat.
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I'll give that the number five.
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And now if we look at the two sentences, they are one, two, three, four and one, two, three,
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five, which already show some form of similarity between them.
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And it's a similarity you'd expect because they're both about loving a pet.
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Given this method of encoding sentences into numbers, now let's take a look at some code to achieve this for us.
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This process, as I mentioned before, is called tokenization, and there's an API for that.
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We'll look at how to use it with Python.
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So here's your first look at some code to tokenize these sentences.
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Let's go through it line by line.
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First of all, we'll need the tokenizer APIs, and we can get these from TensorFlow Keras like this.
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We can represent our sentences as a Python array of strings like this.
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It's simply the I love my dog and I love my cat that we saw earlier.
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Now the fun begins.
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I can create an instance of a tokenizer object.
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The numWords parameter is the maximum number of words to keep.
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So instead of, for example, just these two sentences, imagine if we had hundreds of books to tokenize.
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But we just want the most frequent 100 words in all of that.
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This would automatically do that for us when we do the next step.
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And that's to tell the tokenizer to go through all the text and then fit itself to them like this.
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The full list of words is available as the tokenizer's word index property.
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So we can take a look at it like this and then simply print it out.
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The result will be this dictionary showing the key being the word and the value being the token for that word.
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So, for example, my has a value of three.
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The tokenizer is also smart enough to catch some exceptions.
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So, for example, if we updated our sentences to this by adding a third sentence, noting that dog here is followed by an exclamation mark.
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The nice thing is that the tokenizer is smart enough to spot this and not create a new token.
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It's just dog.
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And you can see the results here.
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There's no token for dog exclamation, but there is one for dog.
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And there's also a new token for the word you.
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If you want to try this out for yourself, I've put the code in a colab here.
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Take it for a spin and experiment.
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You've now seen how words can be tokenized and the tools in TensorFlow that handle that tokenization for you.
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Now that your words are represented by numbers like this, you'll next need to represent your sentences by sequences of numbers in the correct order.
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You'll then have data ready for processing by a neural network to understand or maybe even generate new text.
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You'll see the tools that you can use to manage this sequencing in the next episode.
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So don't forget to hit that subscribe button.

El contexto: aprender a tokenizar para entender el lenguaje natural

En el video, se explica cómo los ordenadores procesan el lenguaje humano a través de la tokenización, un paso fundamental en el Procesamiento de Lenguaje Natural (PLN). Imagina que quieres enseñarle a una máquina a entender frases como "I love my dog" o "I love my cat": la clave está en convertir palabras en números (tokens) para que la red neuronal detecte similitudes, como la conexión entre "dog" y "cat" como mascotas. Este proceso no solo es esencial para la inteligencia artificial, sino que también te ayuda a analizar estructuras lingüísticas, útil incluso para practicar speaking, como en el IELTS.

Trozos útiles y colocaciones para memorizar

  • Tokenization: El proceso de convertir palabras en tokens (números). Ejemplo: "La tokenización permite que los ordenadores comprendan el lenguaje".
  • Word index: Diccionario que asocia cada palabra con su token. Ejemplo: "El word index de 'my' es 3 en el ejemplo del video".
  • Fit to text: Acción de que el tokenizador analice el texto y aprenda sus palabras. Ejemplo: "Al fit to text, el tokenizador identifica las palabras más frecuentes".
  • Most frequent words: Palabras que aparecen con más frecuencia en un corpus. Ejemplo: "En un libro, 'the' y 'and' suelen ser las most frequent words".
  • Neural network: Red de computación que procesa los tokens para entender el significado. Ejemplo: "Una neural network puede detectar sentimientos usando tokens".

Tu reto de shadowing: practica la pronunciación y la fluidez

El shadowing (o "shadowspeak") es una técnica efectiva para mejorar el speaking, especialmente para exámenes como el IELTS. Aquí te mostramos cómo aplicarla con el contenido del video:

  1. Reproduce un fragmento del video (2-3 frases) y escúchalo atentamente, prestando atención a la entonación y la velocidad.
  2. Repite la frase en voz alta inmediatamente después, imitando el tono y la pronunciación. Usa un app de shadowing si lo prefieres para grabarte y comparar.
  3. Focus en palabras clave como "tokenization", "neural network" y "word index": asegúrate de pronunciarlas claramente.
  4. Incrementa la duración de los fragmentos a medida que te sientas más cómodo. Practica diariamente durante 10 minutos para ver resultados rápidos.

Recuerda: el shadowing no solo mejora tu pronunciación, sino también tu capacidad de entender el lenguaje hablado en contextos reales, como el de la inteligencia artificial que vimos. ¡Éxito en tu práctica!

¿Qué es la Técnica de Shadowing?

Shadowing es una técnica de aprendizaje de idiomas respaldada por la ciencia, desarrollada originalmente para la formación de intérpretes profesionales y popularizada por el políglota Dr. Alexander Arguelles. El método es simple pero poderoso: escuchas audio en inglés nativo y lo repites en voz alta de inmediato, como una sombra que sigue al hablante con solo 1-2 segundos de retraso. A diferencia de la escucha pasiva o los ejercicios de gramática, el shadowing obliga a tu cerebro y músculos de la boca a procesar y reproducir simultáneamente patrones de habla reales. Las investigaciones muestran que mejora significativamente la precisión de la pronunciación, la entonación, el ritmo, el habla conectada, la comprensión auditiva y la fluidez al hablar, convirtiéndola en una de las metodologías más efectivas para la preparación del IELTS Speaking y la comunicación en inglés en el mundo real.

Técnica de shadowing: lee la guía completa paso a paso →