Can any of you speak well German with the German lessons. I feel their too short and don't help you memorize the words.
Ja, Deutschunterricht hat mir sehr geholfen (Yes, German lessons have helped me a lot). The grammar and vocabulary will become progressively more difficult as you advance through the lessons.
I suggest the following wording for your question:
Have the German lessons taught you to speak German well? I believe they're too short and don't help with word memorization.
Understand that Duolingo provides a framework for acquiring knowledge of another language. You heard your first language for hundreds of hours before uttering your first intelligible words. You began by simply naming people and things. Gradually you began to make short sentences. By the time you began school the sounds and intonation patterns of that language were well imprinted in your brain. Yet, it is quite possible, that you still could neither read nor write that language. And, by then, you were already about six years old. You've learned one language, therefore, you can learn others. Your ability to read and write will help you. You no longer have the vocabulary base of a pre-schooler. Now, however, YOU are the one who has to do the drill and practice. Be patient with yourself, first. Use the Tiny Cards in Duolingo to practice vocabulary. Make your own flashcards. Name things you own and things that are around you in your room, house, neighborhood, school, workplace, etc.. Use a short sentence such as "Das ist das Haus," and replace 'das Haus' with another noun from the flashcards. Extend the sentence to "Das ist nicht das Haus, das ist der Garten." Repeat words, phrases, and sentences until you can say them easily and rapid-fire. Do the same with pronouns, verb forms, adjectives, and other parts of speech. Review all the cards everyday from each topic and mix them up as you practice. Include questions which are open-ended, "Ist das _ ? Gehen sie _ ? Welche Farbe ist _ ? Ist er _ ? Ich bin __ . You are your own teacher. And, you will gain great satisfaction if you are able to persevere with this project.
Ich wünsche Ihnen viel Glück!
With enough practice, yes. You probably won't be able to speak German after a few weeks of learning, but if you keep at it, fluency will eventually develop. I would say, in most languages, one can start forming sentences and talking when one has reached level 18 or 19 in Duolingo. By level 24, 25 one is quite fluent. Good luck!